Meaning of “mischievous” - Learner’s Dictionary

mischievous

adjective uk us /ˈmɪstʃɪvəs/

behaving in a way that is slightly bad but not serious:

a mischievous grin
a mischievous five-year-old
mischievously adverb

(Definition of “mischievous” from the Cambridge Learner’s Dictionary © Cambridge University Press)