hypergolic Syllabification: (hy·per·gol·ic)Pronunciation: /ˌhīpərˈgälik/Definition of hypergolic adjective (of a rocket propellant) igniting spontaneously on mixing with another substance. Origin: 1940s: from German Hypergol, probably from hyper- 'beyond' + Greek ergon 'work' + -olhypergolic in other Oxford dictionaries Definition of hypergolic in the British & World English dictionary