1.  unofficial(a = adj.all) - not having official authority or sanction; "a sort of unofficial mayor"; "an unofficial estimate"; "he participated in an unofficial capacity"
Antonym: official

2.  unofficial(s = adj.all) - not officially established; "the early election returns are unofficial"

unofficial, adj.
1 not officially authorized or confirmed.
2 not characteristic of officials.

Idiom:
unofficial strike a strike not formally approved by the strikers' trade union.

Derivative:
unofficially adv.

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.