Why was clemency trending last week?
c.1600, "having an overweening opinion of oneself" (short for self-conceited, 1590s); earlier "having intelligence" (1540s); past participle adjective from conceit (q.v.).
late 14c., "something formed in the mind, thought, notion," from conceiven (see conceive) based on analogy of deceit and receipt. Sense evolved from "something formed in the mind," to "fanciful or witty notion" (1510s), to "vanity" (c.1600) through shortening of self-conceit (1580s).