(adv) in a disobedient or naughty way, Syn. mischievously, naughtily, Example:he behaved badly in school; he mischievously looked for a chance to embarrass his sister; behaved naughtily when they had guests and was sent to his room
a. Causing mischief; harmful; hurtful; -- now often applied where the evil is done carelessly or in sport; as, a mischievous child. “Most mischievous foul sin.” Shak. [ 1913 Webster ]
This false, wily, doubling disposition is intolerably mischievous to society. South. [ 1913 Webster ]