Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ĭmĭtātrix, īcis, f. [imitator], she that imitates (rare but class.): boni (voluptas), Cic. Leg. 1, 17, 47: gloriae, id. Tusc. 3, 2, 4: avis imitatrix ac parasita, Plin. 10, 23, 33, § 68.