Word Study
illicit
CIDE DICTIONARY
illicit, a. [L. illicitus; pref. il- not + licitus, p. p. of licere to be allowed or permitted: cf. F. illicite. See In- not, and License.].
Not permitted or allowed; prohibited; unlawful; as, illicit trade; illicit intercourse; illicit pleasure. [1913 Webster]
"One illicit . . . transaction always leads to another."
OXFORD DICTIONARY
illicit, adj. unlawful, forbidden (illicit dealings).
Derivative
illicitly adv. illicitness n.
THESAURUS
illicit
actionable, adulterous, against the law, anarchic, anarchistic, anomic, back-door, banned, barred, black-market, bootleg, chargeable, clandestine, contraband, contrary to law, criminal, extramarital, felonious, flawed, forbade, forbid, forbidden, freeloving, furtive, illegal, illegitimate, impermissible, improper, incestuous, irregular, justiciable, lawless, nonconstitutional, nonlegal, nonlicit, nonpermissible, not permitted, off limits, out of bounds, outlaw, outlawed, prohibited, punishable, ruled out, secret, sneaky, taboo, tabooed, triable, unallowed, unauthorized, unconstitutional, under the ban, under-the-counter, under-the-table, underhanded, unlawful, unlicensed, unofficial, unpermissible, unsanctioned, unstatutory, untouchable, unwarrantable, unwarranted, verboten, vetoed, wrong, wrongfulROGET THESAURUS
illicit
Illegality
N illegality, lawlessness, illicitness, breach of law, violation of law, infraction of the law, disobedience, unconformity, arbitrariness, antinomy, violence, brute force, despotism, outlawry, mob law, lynch law, club law, Lydford law, martial law, drumhead law, coup d'etat, le droit du plus fort, argumentum baculinum, illegality, informality, unlawfulness, illegitimacy, bar sinister, trover and conversion, smuggling, poaching, simony, outlaw, bad man, v, offend against the law, violate the law, infringe the law, break the law, set the law at defiance, ride roughshod over, drive a coach and six through a statute, ignore the law, make the law a dead letter, take the law into one's own hands, smuggle, run, poach, illegal, unlawful, illegitimate, not allowed, prohibited, illicit, contraband, actionable, unwarranted, unwarrantable, unauthorized, informal, unofficial, injudicial, extrajudicial, lawless, arbitrary, despotic, despotical, corrupt, summary, irresponsible, unanswerable, unaccountable, expired, invalid, unchartered, unconstitutional, null and void, a dead letter, lawless, unregulated, illegally, with a high hand, in violation of law.Undueness
N undueness, malum prohibitum, impropriety, illegality, falseness, emptiness of title, invalidity of title, illegitimacy, loss of right, disfranchisement, forfeiture, usurpation, tort, violation, breach, encroachment, presumption, assumption, seizure, stretch, exaction, imposition, lion's share, usurper, pretender, undue, unlawful, unconstitutional, illicit, unauthorized, unwarranted, disallowed, unallowed, unsanctioned, unjustified, unentitled, disentitled, unqualified, disqualified, unprivileged, unchartered, illegitimate, bastard, spurious, supposititious, false, usurped, tortious, undeserved, unmerited, unearned, unfulfilled, forfeited, disfranchised, improper, unmeet, unfit, unbefitting, unseemly, unbecoming, misbecoming, seemless, contra bonos mores, not the thing, out of the question, not to be thought of, preposterous, pretentious, would-be, filius nullius.For further exploring for "illicit" in Webster Dictionary Online