cruel : (adj.) durūra; niddaya; niṭṭhura; kakkhaḷa.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

snying rje med pa

[translation-san] {L} nirdaya

[translation-eng] {Hopkins} non-compassion; pitiless; merciless; cruel

Jeffrey Hopkins' Tibetan-Sanskrit-English Dictionary