early 13c., from Old French deservir (Modern French desservir) "deserve, be worthy of, earn, merit," from Latin deservire "serve well," from de- "completely" (see de-) + servire "to serve" (see serve). From "be entitled to because of good service" (a sense found in Late Latin), meaning generalized c.1300 to "be worthy of." Related: Deserved; deserving.