Entry 1 sense Webster, 1913 Athleticism /ăth-lĕt'-ĭs-ĭzˌ-əm/ · Ath·let·i·cism · IPA /æθˈlɛtɪsɪzəm/ 01 n. The practice of engaging in athletic games; athletism. 1. The practice of engaging in athletic games; athletism.