daftyoudaoicibaDictYouDict[daft 词源字典]
daft: [13] Daft was not always a term of reproach. It originally meant ‘mild, gentle’, and only in late Middle English slid to ‘stupid’ (in a semantic decline perhaps paralleling that of silly, which started off as ‘happy, blessed’). Middle English dafte corresponds directly to an Old English gedæfte, whose underlying sense seems to have been ‘fit, suitable’ (the sense connection was apparently that mild unassuming people were considered as behaving suitably).

There is no direct evidence of its use with this meaning, but Old English had a verb gedæftan ‘make fit or ready, prepare’ which, together with the Gothic verb gedaban ‘be suitable’, points to its origin in a Germanic base *dab- ‘fit, suitable’. This ties in with the semantic development of deft, a variant of daft, which has moved from a prehistoric ‘fit, suitable’ to ‘skilful’.
=> deft[daft etymology, daft origin, 英语词源]
daft (adj.)youdaoicibaDictYouDict
Old English gedæfte "gentle, becoming," from Proto-Germanic *gadaftjaz (cognates: Old English daeftan "to put in order, arrange," gedafen "suitable;" Gothic gadaban "to be fit"), from PIE *dhabh- "to fit together" (see fabric). Sense of "mild, well-mannered" (c. 1200) led to that of "dull, awkward" (c. 1300). Further evolution to "foolish" (mid-15c.), "crazy" (1530s) probably was influenced by analogy with daffe "halfwit" (see daffy); the whole group probably has a common origin.