Entry 1 sense Webster, 1913 Professionalism /prəf-ĕsh'-ən-əl-ĭzˌ-əm/ · Pro·fes·sion·al·ism · IPA /pɹəˈfɛʃənəˌlɪzəm/ 01 n. The following of a profession, sport, etc., as an occupation; -- opposed to amateurism. 1. The following of a profession, sport, etc., as an occupation; -- opposed to amateurism.