*dis- "apart, asunder" (cf. O.E. te-, O.S. ti-, O.H.G. ze-, Ger. zer-). The PIE root is a secondary form of *dwis- and is thus related to L. bis "twice" (originally *dvis) and to duo, on notion of "two-ways, in twain." In classical Latin, dis- paralelled
de- and had much the same meaning, but in L.L. dis- came to be the favored form and this passed into O.Fr. as des-, the form used for new compound words formed in O.Fr., 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.
disalso diss, slang, by 1980, shortening of disrespect or dismiss, originally in U.S. Black English, popularized by hip hop. Related: Dissed; dissing.