Entry 1 sense Webster, 1913 Waning /wān'-ĭng/ · Wan·ing · IPA /ˈweɪ.nɪŋ/ 01 n. The act or process of waning, or decreasing. 1. The act or process of waning, or decreasing. “This earthly moon, the Church, hath fulls and wanings, and sometimes her eclipses.” — Bp. Hall.