allegeyoudaoicibaDictYouDict[allege 词源字典]
allege: [14] Allege is related to law, legal, legislation, legation, and litigation. Its original source was Vulgar Latin *exlitigāre, which meant ‘clear of charges in a lawsuit’ (from ex- ‘out of’ and litigāre ‘litigate’). This developed successively into Old French esligier and Anglo- Norman alegier, from where it was borrowed into English; there, its original meaning was ‘make a declaration before a legal tribunal’.

Early traces of the notion of making an assertion without proof can be detected within 50 years of the word’s introduction into English, but it took a couple of centuries to develop fully. The hard g of allegation suggests that though it is ultimately related to allege, it comes from a slightly different source: Latin allēgātiō, from allēgāre ‘adduce’, a compound verb formed from ad- ‘to’ and lēgāre ‘charge’ (source of English legate and legation).
=> law, legal, legation, legislation, litigation[allege etymology, allege origin, 英语词源]
allege (v.)youdaoicibaDictYouDict
c. 1300. It has the form of one French verb and the meaning of another. The form is Anglo-French aleger, Old French eslegier "to clear at law," from Latin ex- "out of" (see ex-) and litigare "bring suit" (see litigate); however eslegier meant "acquit, clear of charges in a lawsuit." It somehow acquired the meaning of French alléguer, from Latin allegare "send for, bring forth, name, produce in evidence," from ad- "to" (see ad-) + legare "to depute, send" (see legate). Related: Alleged; alleging.