Synonyms of inhumanly

2 Syllables
cruelly
3 Syllables
unkindly, brutally, ruthlessly, viciously, callously, brutishly, ferally, heartlessly
4 Syllables
savagely, mercilessly, atrociously, barbarously, pitilessly
5 Syllables
barbarically, inhumanely, demoniacally, remorselessly