1 anarchic(al), anarchistic, chaotic, unruly, unregulated:
There was a lawless period between the revolution and the establishment of government
2 illegal, illicit, unlawful, criminal, felonious, larcenous, dishonest, corrupt, venal, Colloq crooked:
Holding a demonstration without a permit is a lawless act.
3 villainous, nefarious, wicked, sinful, flagitious, iniquitous, treacherous:
He was once a member of a lawless motor-cycle gang.