But perhaps I could pay you a mina of silver: in that sum, then, I amerce myself.
In your greatness ye shall change it; with your justice ye shall purify it; with your clemencies ye should it chasten and amerce.
Nay, but they will hold thee to ransom, and detain thee till it is brought: I heard them amerce thee at a thousand marks.
I amerce myself, then, to you in that sum; and they will be sufficient sureties for the money.
1215, earlier amercy, Anglo-French amercier "to fine," from merci "mercy, grace" (see mercy). The legal phrase estre a merci "to be at the mercy of" (a tribunal, etc.) was corrupted to estre amercié in an example of how a legalese adverbial phrase can become a verb (cf. abandon). The sense often was "to fine arbitrarily."
Frans hom ne seit amerciez pour petit forfet. [Magna Charta]Related: Amercement; amerciable.