unˈthanking,ppl.a. [un-1 10.] Not giving thanks (for something); ungrateful. 1902Kipling Five Nations (1903) 138 Arid, aloof, incurious, unthinking, unthanking, gelt.1932Chesterton Chaucer i. 36 We may sometimes be unthinking about it; unthinking and especially unthanking.