stupidyoudaoicibaDictYouDict[stupid 词源字典]
stupid: [16] As the related stupefy [16] and stupor [17] still do, stupid originally denoted ‘mental numbness’; ‘lack of intelligence’ is a secondary development. It comes via Old French stupide from Latin stupidus, a derivative of stupēre ‘be stunned or numbed with shock’. This was descended from an Indo-European base *stup- or *tup- ‘hit’, which also produced Greek tüptein ‘hit’ and Sanskrit tup- ‘harm, hurt’.
=> stupefy, stupor[stupid etymology, stupid origin, 英语词源]
stupid (adj.)youdaoicibaDictYouDict
1540s, "mentally slow, lacking ordinary activity of mind, dull, inane," from Middle French stupide (16c.) and directly from Latin stupidus "amazed, confounded; dull, foolish," literally "struck senseless," from stupere "be stunned, amazed, confounded," from PIE *stupe- "hit," from root *(s)teu- (1) "to push, stick, knock, beat" (see steep (adj.)). Related: Stupidly; stupidness.

Native words for this idea include negative compounds with words for "wise" (Old English unwis, unsnotor, ungleaw), also dol (see dull (adj.)), and dysig (see dizzy (adj.)). 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 German töricht vs. dumm but does not exist in most European languages.