This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

v. To give a masculine appearance or character to.

v. To cause (a female) to assume masculine characteristics, as through hormonal imbalance or male hormone therapy.

v. To make masculine; to give typically male characteristics.

v. give a masculine appearance or character to

v. produce virilism in or cause to assume masculine characteristics, as through a hormonal imbalance or hormone therapy

"(A theory: by vibrating their vocal cords to lower the sound they produce, young ladies want to "masculinize" their voices, thereby taking revenge on rampant sexism)."

feminize   

masculinized    masculinizing   

change    modify    alter