Entry 2 senses · 2 variants Webster, 1913 Maniac /mān'-ē-ăkˌ/ · Ma·ni·ac · IPA /ˈmeɪ.niˌæk/ a. n. 01 a. Raving with madness; raging with disordered intellect; affected with mania; mad. 1. Raving with madness; raging with disordered intellect; affected with mania; mad. 02 n. A raving lunatic; a madman. 1. A raving lunatic; a madman.