Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
segnĭtas, ātis, f. [segnis], ante-class. for the class. segnitia, slowness, tardiness, dilatoriness, sluggishness, Att. ap. Non. 174, 23; so id. ib. 174, 21 (in Cic. de Or. 1, 41, 185, and Non. 251, 23; v. segnitia).