English▸ noun (in some sports) an official who watches a game or match closely to enforce the rules and arbitrate on matters arising from the play.
▪ a person chosen to arbitrate between contending parties.
▸ verb [no object] act as an umpire.
▪ [with object] act as umpire in (a game or match).
– ORIGIN late Middle English (originally as noumpere) (denoting an arbitrator): from Old French nonper ‘not equal’. The n was lost by wrong division of a noumpere; compare with adder1.