fawnyoudaoicibaDictYouDict[fawn 词源字典]
fawn: Fawn ‘young deer’ [14] and fawn ‘grovel’ [13] are two distinct words. The latter did not always have the negative associations of ‘servility’ which it usually carries today. Originally it simply referred to dogs showing they were happy – by wagging their tails, for instance. It was a derivative of Old English fægen ‘happy’, an adjective of Germanic origin which survives in the archaic fain ‘willingly’ (as in ‘I would fain go’). Fawn ‘young deer’ comes via Old French faon ‘young of an animal’ and Vulgar Latin *fētō from Latin fētus ‘giving birth, offspring’ (whence English foetus).

The general sense ‘young of an animal’ survived into the early 17th century in English (James I’s translation of the Psalms, for instance, in 1603, has ‘the fawn of unicorns’ in Psalm 29, where the Authorized Version simply refers to ‘a young unicorn’), but on the whole ‘young of the deer’ seems to have been the main sense of the word from the 15th century onwards.

Its use as a colour term, after the pale yellowish brown of a young deer’s coat, dates from the 19th century.
=> fain, foetus[fawn etymology, fawn origin, 英语词源]
fawn (n.)youdaoicibaDictYouDict
"young deer," mid-14c., from Anglo-French (late 13c.), Old French (12c.) faon, feon "young animal," especially "young deer," from Vulgar Latin *fetonem (nominative *feto), from Latin fetus "a bringing forth; an offspring" (see fetus). It was used of the young of any animal as recently as King James I's private translation of the Psalms, but the sense has been mainly of deer since 15c. Color use is by 1881.
fawn (v.)youdaoicibaDictYouDict
Old English fægnian "rejoice, be glad, exult, applaud," from fægen "glad" (see fain); used in Middle English to refer to expressions of delight, especially a dog wagging its tail (early 13c.), hence "court favor, grovel, act slavishly" (early 14c.). Related: Fawned; fawning.