desertion n.

active word-forming element in English and in many verbs inherited from French and Latin, from Latin de "down, down from, from, off; concerning" (see de), also used as a prefix in Latin, usually meaning "down, off, away, from among, down from," but also "down to the bottom, totally" hence "completely" (intensive or completive), which is its sense in many English words.

As a Latin prefix it also had the function of undoing or reversing a verb's action, and hence it came to be used as a pure privative — "not, do the opposite of, undo" — which is its primary function as a living prefix in English, as in defrost (1895), defuse (1943), de-escalate (1964), etc. In some cases, a reduced form of dis-.

Proto-Indo-European root meaning "to line up."

It forms all or part of: assert; assertion; assort; consort; desert (v.) "to leave one's duty;" desertion; dissertation; ensorcell; exert; exsert; insert; seriatim; seriation; series; sermon; serried; sorcerer; sorcery; sort.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit sarat- "thread;" Greek eirein "to fasten together in rows;" Latin serere "to join, link, bind together," series "row, chain, series, sequence, succession;" Gothic sarwa (plural) "armor, arms;" Old Norse sörve "necklace of stringed pearls;" Old Irish sernaid "he joins together;" Welsh ystret "a row."