Entry 1 sense Webster, 1913 Platitudinarian · Plat·i·tu·di·na·ri·an · IPA /ˌplætɪˌtudəˈtɛɹi.ən/ 01 n. One addicted to uttering platitudes, or stale and insipid truisms. 1. One addicted to uttering platitudes, or stale and insipid truisms.