Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
nī̆grĭtĭa, ae, and nī̆grĭtĭes, ēi, f. [1. niger], black color, blackness (post-Aug.): capilli, Plin. 29, 6, 34, § 109; 9, 38, 62, § 134.
Form nigrities, Cels. 8, 4, 19; 5, 20, 3 al.