What is the X in X-mas?
c.1300, from Anglo-French avoider "to clear out, withdraw (oneself)," partially anglicized from Old French esvuidier "to empty out," from es- "out" (see ex-) + vuidier "to be empty," from voide "empty, vast, wide, hollow, waste" (see void (adj.)). Originally a law term; modern sense of "have nothing to do with" also was in Middle English and corresponds to Old French eviter with which it was perhaps confused. Meaning "escape, evade" first attested 1520s. Related: Avoided; avoiding.