mero motu

adv

Etymology: From post-classical Latin motu mero (with transposition of elements), ablative of motus merus (“free impulse, volition”), from classical Latin mōtus (“motion, movement”).

1. (Of) one's own accord.

   “I charge thee, write not a word to me in her favour, if thou meanest her well; for if I spare her, it must be all ex mero motu.”