ETYM Latin illicitus; pref. il- not + licitus, p. p. of licere to be allowed or permitted: cf. French illicite. Related to In- not, and License.
(Homonym: elicit).
Contrary to accepted morality (especially sexual morality) or convention.

1. Not endowed with authority.
2. Without official authorization; SYN. wildcat.

Unlawfully, improperly, illegally, illegitimately