word-forming element of Latin origin meaning 1. "lack of, not" (as in dishonest); 2. "opposite of, do the opposite of" (as in disallow); 3. "apart, away" (as in discard), from Old French des- or directly from Latin dis- "apart, asunder, in a different direction, between," figuratively "not, un-," also "exceedingly, utterly." Assimilated as dif- before -f- and to di- before most voiced consonants.
The Latin prefix is from PIE *dis- "apart, asunder" (source also of Old English te-, Old Saxon ti-, Old High German ze-, German zer-). The PIE root is a secondary form of *dwis- and thus is related to Latin bis "twice" (originally *dvis) and to duo, on notion of "two ways, in twain" (hence "apart, asunder").
In classical Latin, dis- paralleled de- and had much the same meaning, but in Late Latin dis- came to be the favored form and this passed into Old French as des-, the form used for compound words formed in Old French, where it increasingly had a privative sense ("not"). In English, many of these words eventually were altered back to dis-, while in French many have been altered back to de-. The usual confusion prevails.
As a living prefix in English, it reverses or negatives what it is affixed to. Sometimes, as in Italian, it is reduced to s- (as in spend, splay, sport, sdain for disdain, and the surnames Spencer and Spence).
early 15c., "to rest or be satisfied; to give satisfaction to," from Old French contenter (from content (adj.) "satisfied") and Medieval Latin contentare, both from Latin contentus "contained; satisfied," past participle of continere "to hold together, enclose," from assimilated form of com "with, together" (see con-) + tenere "to hold" (from PIE root *ten- "to stretch").
Sense connection of "contained" and "satisfied" probably is that the contented person's desires are bound by what he or she already has. Related: Contented; contenting.
c. 1400, literally "held or contained within limits," hence "having the desire limited to present enjoyments," from Old French content, "satisfied," from Latin contentus "contained, satisfied," past participle of continere "to hold together, enclose," from assimilated form of com "with, together" (see con-) + tenere "to hold" (from PIE root *ten- "to stretch"). Related: Contently (largely superseded by contentedly).
<a href="https://www.etymonline.com/word/discontent">Etymology of discontent by etymonline</a>
Harper, D. (n.d.). Etymology of discontent. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/discontent