From 'akzar; terrible -- cruel (one).
see HEBREW 'akzar
H394. akzari
אַכְזָרִי adjective cruel, always in this form; — Proverbs 12:10; 17:11; Jeremiah 6:23; 50:42, also 30:14 (read א ׳מוּסָר, for מוּסַר ᵑ0, Gf Gie); as substantive Proverbs 5:9; 11:17, perhaps also, in apposition with י ׳יוֺם, Isaiah 13:9.