defalcation

Late 15th century, from Medieval Latin dēfalcātiōnem, accusative singular of dēfalcātiō (literally “cutting off, lopping off with a sickle”), nominalization of dēfalcō, from Latin dē (“off”) + falx (“sickle, scythe, pruning hook”), from which also English falcate (“sickle-shaped”). By surface analysis, defalcate + -ion (“the act of”).