Lewis & Short

ămātrĭx, īcis, f. [amator], a female lover, in an honorable and a dishonorable sense, a mistress, sweetheart (syn.: amans, amica): Sappho amatrix, Mart. 7, 69, 9: dicacula, Plaut. As. 3, 1, 8; id. Poen. 5, 5, 25.
Used as adj.: amatrices aquae, amorous, Mart. 7, 15; 10, 4.