1) Callously 2) Cruelly 3) Disagreeably 4) Distastefully 5) Harshly 6) Heartlessly 7) Horribly 8) Horridly 9) How dastards speak 10) Hurtfully 11) In a mean manner 12) Maliciously 13) Meanly 14) Objectionably 15) Obnoxiously 16) Offensively 17) Repulsively 18) Ruthlessly 19) Spitefully 20) Unattractively 1) Cruelly 2) Malevolently 3) Maliciously 4) Meanly 5) Rudely 6) Spitefully 7) Unkindly 8) Unpleasantly 
• (adv.) In a nasty manner. • (adv.) In a nasty manner.
Nas'ti·ly adverb In a nasty manner. 
[adv] - in a nasty ill-tempered manner
adverb in a nasty ill-tempered manner; ``Don`t expect me to help you,` he added nastily`