disproportion n.

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).

late 14c., proporcioun, "due relation of one part to another," also "size, extent; comparative relation of one thing to another in size, degree, number, etc.," from Old French proporcion "measure, proportion" (13c.) and directly from Latin proportionem (nominative proportio) "comparative relation, analogy," from phrase pro portione "according to the relation" (of parts to each other), from pro "for" (see pro-) + ablative of *partio "division," related to pars "a part, piece, a share, a division" (from PIE root *pere- (2) "to grant, allot"). Also from late 14c. as "relation of body parts," hence "form, shape." Phrase out of proportion attested by 1670s.

My fortunes [are] as ill proportioned as your legs. [John Marston, "Antonio and Mellida," 1602]