mischievous

/ˈmɪs.t͡ʃə.vəs/

adjective

Meaning

Causing mischief; injurious.
Troublesome, cheeky, badly behaved.
"Matthew had a twin brother called Edward, who was always mischievous and badly behaved."

Synonyms

badly-behaved,

naughty,

destructive,

detrimental,

harmful,

hurtful,

noxious,

pernicious