fallowyoudaoicibaDictYouDict[fallow 词源字典]
fallow: English has two words fallow, both of considerable antiquity. Fallow ‘uncultivated’ [OE] originally meant ‘ploughed land’. Its present-day adjectival meaning ‘ploughed but not sown’ or, more broadly, just ‘uncultivated’, developed in the 15th century. Fallow ‘pale yellowish-brown’ [OE] (now used only in fallow deer) comes via Germanic *falwaz from Indo- European *polwos, a derivative of the base *pol-, *pel-, which also produced English appal [14] (originally ‘grow pale’), pale, and pallid.

Its Germanic relatives include German fahl ‘pale, fawn’ and falb ‘pale yellow’. (Germanic *falwaz, incidentally, was the ancestor of French fauve ‘wild animal’, source of the term fauvism [20] applied to an early 20th-century European art movement that favoured simplified forms and bold colours.)
=> appal, pale, pallid[fallow etymology, fallow origin, 英语词源]
doe (n.)youdaoicibaDictYouDict
Old English da "a female deer," of unknown origin, perhaps a Celtic loan-word (compare Cornish da "fallow deer," Old Irish dam "ox," Welsh dafad "sheep").