Entry 1 sense Webster, 1913 Outnumber /out-nŭm'-bẽr/ · Out·num·ber · IPA /aʊtˈnʌmbə(ɹ)/ 01 v. t. To exceed in number; as, the garrison was badly outnumbered by the attacking forces. 1. To exceed in number; as, the garrison was badly outnumbered by the attacking forces.