deteriorate (v.)

Latin adverb and preposition of separation in space, meaning "down from, off, away from," and figuratively "concerning, by reason of, according to;" from PIE demonstrative stem *de- (see to). Also a French preposition in phrases or proper names, from the Latin word.

"a growing or making worse," 1650s, possibly a native formation, or else from French détérioration (15c.), noun of action from détériorer, from Late Latin deteriorare "get worse; make worse" (see deteriorate).