Anasuya (अनसूया), literally meaning free from envy and jealousy, was the wife of an ancient Indianrishi (sage) named Atri. In the Ramayana, she appears living with her husband in a small hermitage in the southern periphery of the forest of Chitrakuta. She was very pious, and always practiced austerities and devotion. This made her attain miraculous powers. When Sita and her husband Rama visited her during their exile, Anasuya was very attentive to them, and gave Sita an ointment which was to keep her beautiful for ever. She was mother of the irascible sage Durvasa. Anasuya was also a friend of Shakuntala. The name is also spelled Anusuya.
She was the daughter of Sage Kadram and his wife Devhuti. Sage Kapila was her brother and teacher.
References
A Dictionary of Hindu Mythology & Religion by John Dowson