1 mischievous, impish, puckish, roguish, scampish, devilish; frolicsome, playful:
The children would get naughty the minute the teacher turned her back to the class.
2 disobedient, refractory, insubordinate, bad, perverse, wicked, fractious, unruly, wayward, unmanageable, ungovernable, undisciplined, defiant, obstreperous:
Naughty pupils in this school are birched.
3 improper, offensive, vulgar, indecent, immoral, risqué, off colour, ribald, bawdy, blue, pornographic, smutty, lewd, obscene, dirty, Colloq X-rated, raunchy:
The teacher caught Keith reading a naughty book.