1766, "allege to be of unsound mind" (legal term), from Late Latin stultificare "turn into foolishness," from Latin stultus "foolish" (literally "uneducated, unmovable," from PIE root *stel- "to put, stand") + root of facere "to make" (see factitious). The first element is cognate with Latin stolidus "slow, dull, obtuse" (see stolid). Meaning "cause to appear foolish or absurd" is from 1809. Hence stultiloquy "foolish talk, silly babbling" (1650s). Related: Stultified; stultifying.