stfantasy /ˈstɛˈfæntəsi/ noun1 •(slang, old-fashioned) The overall field of literature containing the genres of science fiction and fantasy fiction; imaginative fiction; speculative fiction.The average stefnist eats up good stfantasy, has an exaggerated idea of its literary merit, and will leap to defend it against detractors. — 1944 formsstfantasies