To make something or someone more characteristic of or associated with women. The fashion industry has started to feminize traditional men's clothing by adding softer fabrics and pastel colors.
To cause a male to develop female characteristics, often through hormonal treatment. The doctor explained how certain medications could feminize the patient as part of the treatment process.
(Linguistics) To mark or modify a word so that it belongs to the feminine grammatical gender. In Spanish, you can feminize certain adjectives by replacing the final ‑o with ‑a.