faryoudaoicibaDictYouDict[far 词源字典]
far: [OE] Far is a word of ancient ancestry. It goes back to Indo-European *per-, which also produced Greek pérā ‘beyond, further’ and Sanskrit paras ‘beyond’. The Germanic descendant of the Indo-European form was *fer-, whose comparative form *ferrō ‘further’ passed into Old English as feorr, having lost its comparative connotations and come to mean simply ‘far’.

The Old English comparative was fierr, but in early Middle English this too lost its comparative force and a new form was created with the -er ending, ferrer, later farrer. This in turn was gradually replaced by further (a completely different – although probably distantly related – word, based on forth), of which farther is a 13th-century variant modelled on far.
[far etymology, far origin, 英语词源]
far (adj.)youdaoicibaDictYouDict
Old English feorr "far, remote, distant" (cognates: Old Saxon fer, Old Frisian fer, Old Norse fjarre, Dutch ver, Old High German ferro, German fern), probably a development in western Proto-Germanic from the adverb (see far (adv.)). Far East "China, Japan, and surrounding regions" is from 1838.
far (adv.)youdaoicibaDictYouDict
Old English feor "to a great distance, long ago," from Proto-Germanic *ferro (cognates: Old Saxon fer, Old Frisian fir, Old Norse fiarre, Old High German fer, Gothic fairra), from PIE *per (1), base of words for "through, forward," with extended senses such as "across, beyond" (cognates: Sanskrit parah "farther, remote, ulterior," Hittite para "outside of," Greek pera "across, beyond," Latin per "through," Old Irish ire "farther"). Paired with wide since 9c.