Synonyms and related words :
cruelty, flat refusal, flintiness, hardness, harshness, heartlessness, inclemency, inexorableness, mercilessness, pitilessness, point-blank refusal, rebuff, relentlessness, remorselessness, repulse, ruthlessness, summary negative, tender mercies, uncompassionateness, unfeelingness, unforgivingness, unmercifulness, unremorsefulness, unsympatheticness, unyieldingness