stupid Look up stupid at Dictionary.com
1540s, "mentally slow," from M.Fr. stupide, from L. stupidus "amazed, confounded," lit. "struck senseless," from stupere "be stunned, amazed, confounded," from PIE *(s)tupe- "hit," from base *(s)teu- (see steep (adj.)). Native words for this idea include negative compounds with words for "wise" (cf. O.E. unwis, unsnotor, ungleaw), also dol (from root of Ger. toll "mad," related to Gk. tholeros "muddy, turbid"), and dysig (see dizzy). Stupid retained its association with stupor and its overtones of "stunned by surprise, grief, etc." into mid-18c. The difference between stupid and the less opprobrious foolish roughly parallels that of Ger. töricht vs. dumm but does not exist in most European languages.