kṭvtu (p. 87) . A defective verb used in the optative form, expressing, 1st. The duty of doing a thing; 2d. Desire--as போகக்கடவாய், O! that thou wouldst go; 3d. Sometimes ஆக is affixed to it, and then it serves to denote the present, imperfect and future optative. செய்யக்கடவராக. May he do so. 30)