dishonorable (adj.)

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).

mid-14c. (mid-13c. as a surname, Walter le Onorable, also known as Walter Honurable), "worthy of respect or reverence, respectable," also "signifying or rendering distinction or respect; ensuring good repute or honor," from Old French onorable, honorable "respectable, respectful, civil, courteous," from Latin honorabilis "that procures honor, estimable, honorable," from honorare "to honor," from honor (see honor (n.)). Meaning "honest, sincere, in good faith" is from 1540s; sense of "acting justly" is from c. 1600.

"Now, George, you must divide the cake honorably with your brother Charlie."—George: "What is 'honorably,' mother?" "It means that you must give him the largest piece."—George: "Then, mother, I should rather Charlie would cut it." ["Smart Sayings of Bright Children," collected by Howard Paul, 1886]

As an epithet before the name of a peer, Church or civil official, guild officer, etc., from c.1400. As a noun, "honorable person," late 14c. Alternative adjective honorous (Old French honoros) seems not to have survived Middle English. Related: Honorably; honorableness.