late 14c., "hateful, odious, atrocious," from Old French hainos "inconvenient, awkward; hateful, unpleasant; odious" (12c., Modern French haineux), from haine "hatred, hate,&q [..]

flagitious: extremely wicked, deeply criminal; "a flagitious crime"; "heinous accusations" (heinously) in a terribly evil manner; "the [..]

adj. Odiously sinful.

enormously and shockingly evil [a crime] hei·nous·ly adv hei·nous·ness n

Heinous means hateful or shockingly evil. A grossly wicked or reprehensible action is called heinous act. The term is mostly used to refer to crimes. For example, heinous murder.

(adj) extremely wicked, deeply criminal

Totally reprehensible. ''I hope they catch the person responsible for that heinous crime.'' ''The perpetrators of this heinous act must be brought to justice.'' ''The government denounced the [..]