Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
in-diffĕrentĭa, ae, f. [indifferens], want of distinction or difference, similarity, equivalence (post-class.): utriusque vocabuli, Gell. 13, 3, 6; Hier. in Didym. de Spir. Sanc. 1, 20.