mischievous

Etymology

From Middle English myschevous, mischevous, from Anglo-Norman meschevous, from Old French meschever, from mes- (“mis-”) + chever (“come to an end”) (from chef (“head”)). Synchronically analyzable as mischief + -ous.

adj

1. Causing mischief; injurious.
   ...; that good and bad actions at present are naturally rewarded and punished, not only as beneficial and mischievous to society, but also as virtuous and civious; ... 1793, Joseph Butler, The Analogy of Religion
   On the whole, therefore, he concludes that the point of indulgence at which these self-passions or self-affections begin to be mischievous to the individual coincides with that at which they begin to be mischievous to society; ... 1892, Henry Sidgwick, Outlines of the History of Ethics
2. Troublesome, cheeky, badly behaved.
   Matthew had a twin brother called Edward, who was always mischievous and badly behaved.