Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sĕdentārĭus, a, um, adj. [sedeo], of or belonging to sitting, sitting, sedentary (very rare): sutores, Plaut. Aul. 3, 5, 39; cf. opera, Col. 12, 3, 8: necessitas assentiendi, of giving assent while sitting, i. e. without rising to make a speech, Plin. Pan. 73, 3: fatigatio, fatigue from sitting, App. M. 1 init.