pitiless
1. [ adjective ] without mercy or pity
Synonyms: ruthless remorseless unpitying
Examples:

"an act of ruthless ferocity" "a monster of remorseless cruelty"

Related terms: merciless
2. [ adjective ] deficient in humane and kindly feelings
Synonyms: unkind
Related terms: inhumane
Similar spelling:   pitilessly