Entry 1 sense Webster, 1913 Inhibitor /ĭnˌ-hĭb'-ət-ẽr/ · In·hib·i·tor · IPA /ɪnˈhɪbɪtɚ/ 01 n. That which causes inhibitory action; esp., an inhibitory nerve. 1. That which causes inhibitory action; esp., an inhibitory nerve.