coldhearted

bloodless, hard-hearted, heartless, kindless, pitiless, uncaring, unfeeling

antiseptic, arctic, brittle, chill, chilly, clammy, cold, cold-blooded, cold-eyed, coldish, cool, frigid, frosty, frozen, gelid, glacial, hard-eyed, icy, uncordial, unfriendly, unsympathetic, wintry (also wintery)

reserved, soulless, undemonstrative, unemotional, unresponsive

apathetic, indifferent, unenthusiastic, uninterested

aloof, detached, dispassionate, impersonal, offish, standoffish

antisocial, unsociable, unsocial