Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
perfectĭo, ōnis, f. [perficio], a finishing, completing, perfecting; perfection (class.): hanc absolutionem perfectionemque in oratore desiderans, Cic. de Or. 1, 28, 130: perfectio atque absolutio optimi, id. Brut. 36, 137: ad cumulum perfectionis accedere, Greg. M. Ep. 7, 10 fin.; Cic. Or. 29, 103; id. Fin. 3, 9, 32; Vulg. Num. 6, 21.
Plur.: operum perfectiones, Vitr. 3, 1, 4.