In every language, a word can be "basic" or composite, actually. Basic words are those words that cannot be broken into parts. Other words, instead, are made of a root (a part that cannot stand on its own) and affixes (either prefixes or suffixes). On one hand, breaking a word into parts has a definite impact on your understanding of its meaning. On the other hand, having a clear understanding of the root and the affixes permits you to master several words that stems from the same seed and catch the meaning of other words, easily, that are not in your vocabulary or are unknown to you!

The following tables are useful for your GRE vocabulary. I tried to create a list that at the same time

• covers as many as possible both the roots and the affixes;
• is not just a list of words to memorize in a sterile way but easy to remember;
• contains a lot of words useful not only to improve your vocabulary skills as a whole but also words contained in the verbal part of the GRE.

GENERAL ROOTS AND PREFIXES #1
Root or Prefix	Meaning	Examples
a, an	not, without	atheist, anarchy, anonymous apathy, aphasia, anemia, atypical, anesthesia
ab	away from	absent, abduction, aberrant, abstemious, abnormal, abstract, absorb
acro	high, tip, top	acrobat, acrophobia, acronym, acromegaly
ad	to, toward	admit, addition, advertisement, adherent, admonish, address, adhesive, adept, adjust
alt	high	altitude, altimiter, alto, contralto, altocumulus
ambul	to walk	ambulatory, amble, ambulance, somnambulist, perambulate, preamble
ante	before	anteroom, antebellum, antedate antecedent, antediluvian
anti, ant	against, opposite	antisocial, antiseptic, antithesis, antibody, antichrist, antinomies, antifreeze, antipathy, antigen, antibiotic, antidote, antifungal, antidepressant
audi	to hear	audience, auditory, audible, auditorium, audiovisual, audition, audiobook
auto	self	automobile, automatic, autograph, autonomous, autoimmune, autopilot, autobiography
be	thoroughly	bedecked, besmirch, besprinkled, begrudge, begrime, belie, bemoan
bell	war	belligerent, antebellum, bellicose, rebel
bene	good, well	benefactor, beneficial, benevolent, benediction, beneficiary, benefit
bi	two	bicycle, bifocals, biceps, billion, binary, bivalve, bimonthly,bigamy, bimetal, biathlete, bicarbonate
cede, ceed, cess	to go, to yield	succeed, proceed, precede, recede, secession, exceed, succession, excess
chron	time	chronology, chronic, chronicle, chronometer, anachronism
cide, cis	to kill, to cut	fratricide, suicide, incision, excision, circumcision, precise, concise, precision
circum	around	circumnavigate, circumflex, circumstance, circumcision, circumference, circumorbital, circumlocution, circumvent, circumscribe, circulatory
clud, clus claus	to close	include, exclude, clause, claustrophobia, enclose, exclusive
con, com	with, together	convene, compress, contemporary, converge, compact, confluence, concatenate, conjoin, combine, convert, compatible, consequence

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GENERAL ROOTS AND PREFIXES #2
Root or Prefix	Meaning	Examples
contra, counter	against, opposite	contradict, counteract, contravene, contrary, counterspy, contrapuntal, contraband
cred	to believe	credo, credible, credence, credit, credential, credulity, incredulous, creed, incredible
commun	to share	commune, community, communism, communicable, communication, commonality, incommunicado
cycl	circle, wheel	bicycle, cyclical, cycle, encliclical, motorcycle, tricycle, cyclone
de	from, down, away	detach, deploy, derange, deodorize, devoid, deflate, degenerate, deice, descend, derail, depress, depart, decompose, destruction
dei, div	God, god	divinity, divine, deity, divination, deify
demo	people	democracy, demagogue, epidemic, demographic
dia	through, across, between	diameter, diagonal, dialogue, dialect, dialectic, diagnosis, diachronic, diagram, diaphragm
dict	speak	predict, verdict, malediction, dictionary, dictate, dictum, diction, indict, contradict
dis, dys, dif	away, not, negative	dismiss, differ, disallow, disperse, dissuade, disconnect, dysfunction, disproportion, disrespect, distemper, distaste, disarray, dyslexia
duc, duct	to lead, pull	produce, abduct, product, transducer, viaduct, aqueduct, induct, deduct, reduce, induce
dyn, dyna	power	dynamic, dynamometer, heterodyne, dynamite, dynamo, dynasty
ecto	outside, external	ectomorph, ectoderm, ectoplasm, ectopic, ectothermal
endo	inside, withing	endotoxin, endoscope, endogenous
equi	equal	equidistant, equilateral, equilibrium, equinox, equitable, equation, equator
e, ex	out, away, from	emit, expulsion, exhale, exit, express, exclusive, enervate, exceed, explosion
exter, extra	outside of	external, extrinsic, exterior, extraordinary, extrabiblical, extracurricular, extrapolate, extraneous, exterminator, extract, extradite, extraterrestrial, extrasensory, extravagant, extreme
flu, flux	flow	effluence, influence, effluvium, fluctuate, confluence, reflux, influx
flect, flex	to bend	flexible, reflection, deflect, circumflex, inflection, reflex
graph, gram	to write	polygraph, grammar, biography, graphite, telegram, autograph, lithograph, historiography, graphic, electrocardiogram, monogram

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GENERAL ROOTS AND PREFIXES #3
Root or Prefix	Meaning	Examples
hetero	other	heterodox, heterogeneous, heterosexual, heterodyne
hyper	over, above	hyperactive, hypertensive, hyperbolic, hypersensitive, hyperventilate, hyperkinetic, hyperlink, hypertext, hypersonic, hypertrophy
homo	same	homogenized, homosexual, homonym, homophone
hypo	below, less than	hypotension, hypodermic, hypoglycemia, hypoallergenic, hypothermia, hypothesis
in, im	not	inviolate, innocuous, intractable, innocent, impregnable, impossible
infra	beneath	infrared, infrastructure, infrasonic
inter, intro	between	international, intercept, intermission, interoffice, internal, intermittent, introvert, introduce
intra	within, into	intranet, intracranial, intravenous, intramural, intramuscular, intraocular
jac, ject	to throw	reject, eject, project, trajectory, interject, dejected, inject, ejaculate
mal	bad,badly	malformation, maladjusted, dismal, malady, malcontent, malfeasance, maleficent, malevolent, malice, malaria, malfunction, malignant
mega	great, million	megaphone, megalomaniac, megabyte, megalopolis
meso	middle	mesomorph, mesoamerica, mesosphere
meta	beyond, change	metaphor, metamorphosis, metabolism, metahistorical, metainformation, metacognitive
meter	measure	perimeter, micrometer, ammeter, multimeter, altimeter, geometry, kilometer
micro	small	microscope, microprocessor, microfiche, micrometer, micrograph
mis	badly	misinform, misinterpret, mispronounce, misnomer, mistake, misogynist
mit, miss	to send	transmit, permit, missile, missionary, remit, admit, missive, mission
morph	shape	polymorphic, morpheme, amorphous, metamorphosis, morphology, morphing
multi	many	multitude, multipartite, multiply, multipurpose, multicolored, multimedia, multinational
neo	new	neologism, neonate, neoclassic, neophyte

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GENERAL ROOTS AND PREFIXES #4
Root or Prefix	Meaning	Examples
non	not	nonferrous, nonabrasive, nondescript, nonfat, nonfiction, nonprofit, nonsense, nonentity
omni	all	omnipotent, omnivorous, omniscient, omnibus, omnirange, omnipresent
para	beside	paraprofessional, paramedic, paraphrase, parachute, paralegal, parallel, comparison
per	through, intensive	permit, perspire, perforate, persuade, perceive, perfect, permit
peri	around	periscope, perimeter, perigee, periodontal
phon	sound	telephone, phonics, phonograph, phonetic, homophone, microphone
phot	light	photograph, photosynthesis, photon
poly	many	polytheist, polygon, polygamy, polymorphous
port	to carry	porter, portable, report, transportation, deport, import, export
re	back, again	report, realign, retract, revise, regain, reflect, rename, restate, recombine, recalculate, redo
retro	backwards	retrorocket, retrospect, retrogression, retroactive
sanct	holy	sanctify, sanctuary, sanction, sanctimonious, sacrosanct
scrib, script	to write	inscription, prescribe, proscribe, manuscript, conscript, scribble, scribe
sect, sec	cut	intersect, transect, dissect, secant, section
semi	half	semifinal, semiconscious, semiannual, semimonthly, semicircle
spect	to look	inspect, spectator, circumspect, retrospect, prospect, spectacle
sub	under, below	submerge, submarine, substandard, subnormal, subvert, subdivision, submersible, submit
super, supra	above	superior, suprarenal, superscript, supernatural, supercede, superficial, superhero, superimpose
syn	together	synthesis, synchronous, syndicate, synergy, snyopsis, syncretism
tele	distance, from afar	television, telephone, telegraph, telemetry, telepathy

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GENERAL ROOTS AND PREFIXES #5
Root or Prefix	Meaning	Examples
theo, the	GOD	theology, theist, polytheist, pantheism, atheist
therm, thermo	heat	thermal, thermometer, thermocouple, thermodynamic, thermoelectric
tract	to drag, draw	attract, tractor, traction, extract, retract, protract, detract, subtract, contract, intractable
trans	across	transoceanic, transmit, transport, transducer
un	not	uncooked, unharmed, unintended, unhappy
veh, vect	to carry	vector, vehicle, convection, vehement
vert, vers	to turn	convert, revert, advertise, versatile, vertigo, invert, reversion, extravert, introvert
vita	life	vital, vitality, vitamins, revitalize

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SUFFIXES #6
Root or Prefix	Meaning	Examples
able, ible	able to be, capable of being	pourable, drinkable, readable, washable, curable, visible, flexible, collectible
ance, ancy	state of, process of	performance, reliance, defiance, radiance, acceptance, ascendancy, discrepancy, infancy
dom	condition, office, state	kingdom, freedom, wisdom, sheikdom, fiefdom, sheikdom
ee	one who receives	payee, mortgagee, employee, appointee, abductee, examinee, referee, refugee
er, or	one who does [the verb]	driver, hiker, reader, manager, polisher, speaker, counselor, author, creator, director, sculptor
ful	filled with	frightful, delightful, wonderful, cupful, wakeful, bashful, bountiful, beautiful, cheerful, colorful, dreadful, fateful
ify	to make into	purify, deify, simplify, clarify, petrify
ification	process of making into	purification, deification, simplifiction, clarification, petrification
ish	the nature of, resembling	cornish, Irish, bookish, freakish, foolish, boorish, selfish, sluggish, priggish
ism	doctrine, system, characteristic quality	capitalism, heroism, optimism, skepticism, realism, patriotism, communism, idealism, conservatism
ist	one who performs; an adherent of an ism	tympanist, cellist, idealist, communist, realist, moralist, pharamacist, pragmatist
ize	to make into	rationalize, normalize, realize, capitalize
ization	the process of making into	rationalization, normalization, realization, capitalization
less	without	bottomless, effortless, friendless, noiseless, harmless

source: https://www.redwoods.edu/
https://www.litinfocus.com/120-root-wor ... -pdf-list/
https://dcps.duvalschools.org/cms/lib07 ... 0level.pdf