'masculinise' originates from French, specifically the word 'masculiniser', where the root 'masculin-' (from Latin 'masculus') meant 'male, masculine'.

'masculinise' changed from French 'masculiniser' (Modern French), which in turn comes from Late Latin/French use of Latin 'masculus' ('male'); the English verb entered via French formation (masculin- + -ise) and became 'masculinise' (British spelling) in Modern English.

Initially it meant 'to make male' or 'to render masculine'; over time it has retained that core meaning but has broadened to include making things or traits culturally or socially masculine (e.g., language, institutions, styles).