Unlawful, a. — Webster enters it under “unlawful”
Not lawful; contrary to law. -- Un*law"ful*ly, adv. -- Un*law"ful*ness, n. Unlawful assembly. (Law) See under Assembly.
Shades of meaning
Fernald lists unlawfulness only as an antonym, under justice.
He lists it without comment; the entries above explain its neighbors.
Synonyms
none given