remorse: [14] Remorse etymologically denotes the ‘biting’ of conscience. The word comes ultimately from medieval Latin remorsus ‘torment’, a derivative of Latin remordēre ‘bite back’, hence ‘torrnent’. This was a compound verb formed from the prefix re- ‘back, again’ and mordēre ‘bite’ (source of English morsel). The noun was used in the expression remorsus conscientiae ‘torment of conscience’, which passed into Old French as remors de conscience. English adopted this at the end of the 14th century, and by the beginning of the 15th century remorse was being used on its own in the same sense. => morsel[remorse etymology, remorse origin, 英语词源]