In English context hentai is what you stated, but in Japan it isn’t necessarily: “変態 【へんたい】 (n,vs,adj-no) (1) transformation; (2) abnormality; (3) (abbr) (See 変態性欲) sexual perversion; pervert; (4) {biol} metamorphosis; (5) {chem; physics} transformation; transition; modification”