petrify கல்லாகு kallāku (kallaahu) (3b intr) (of heart) turn into a stone; (of body) become toughened and hard
Usage:
அவனுடைய இதயம் கல்லாகிப்போனது போலத் தெரிகிறது avaṉuṭaiya itayam kallākippōṉatu pōlat terikiṟatu avanooḍa idayam kallaahipoonadu maadiri teriyudu His heart seems to have petrified and turned to stone.