Synonyms and related words :
callous, cruel, disagreeable, flinty, hard, harsh, heartless, ill, inconsiderate, inflexible, inhospitable, inhuman, insensitive, mean, rigid, severe, stern, thoughtless, tough, unaffectionate, unamiable, unbending, unbenign, unbenignant, uncaring, uncharitable, unchristian, uncompassionate, uncompassioned, unconcerned, uncordial, unfeeling, ungenial, ungracious, unkindly, unloving, unsympathetic, unsympathizing, unthoughtful, unyielding