Musnad Ahmad 25:453

Khalaf ibn al-Walid narrated to us, Khalid narrated to us, from Yazid ibn Abi Ziyad, from Ikrimah, from Ibn Abbas, who said: "The Messenger of Allah, may Allah bless him and grant him peace, cursed the effeminate men and the masculine women." He said: So I said: "What are the masculine women?" He said: "The women who imitate men."