Entry 1 sense Webster, 1913 Gargantuan /gär-găn'-cho͞o-ən/ · Gar·gan·tu·an · IPA /ɡɑɹˈɡæn.t͡ʃu.ən/ 01 a. Characteristic of Gargantua, a gigantic, wonderful personage; enormous; prodigious; inordinate. 1. Characteristic of Gargantua, a gigantic, wonderful personage; enormous; prodigious; inordinate.