1) Brutal 2) Callous 3) Cruel 4) Cruel, harsh 5) Cutting 6) Edged 7) Grinchlike 8) Harsh 9) Harsh; cruel 10) Heartless 11) Hurtful 12) Inconsiderate, harsh 13) Lacking consideration 14) Lacking in kindness or mercy 15) Lacking kindness 16) Malevolent 17) Malicious 18) Malign 19) Mean 20) Mean-spirited 1) Callous 2) Catty 3) Cold-hearted 4) Coldhearted 5) Cruel 6) Cutting 7) Heartless 8) Hurtful 9) Inconsiderate 10) Indiscreet 11) Inhumane 12) Kindless 13) Malicious 14) Malign 15) Mean 16) Merciless 17) Sarcastic 18) Scathing 19) Selfish 20) Snide 21) Spiteful 22) Uncharitable 23) Unkindly 24) Unmerciful 
• (a.) Not kind; contrary to nature, or the law of kind or kindred; unnatural. • (a.) Having no race or kindred; childless. • (a.) Wanting in kindness, sympathy, benevolence, gratitude, or the like; cruel; harsh; unjust; ungrateful.
[adj] - lacking kindness
adjective lacking kindness; `a thoughtless and unkind remark`; `the unkindest cut of all`
lacking in kindness or mercy; severe.