Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
* tardĭgrădus, a, um, adj. [tardusgradior], slow-paced, tardy-paced: quadrupes, Pac. ap. Cic. Div. 2, 64, 133 (Trag. v. 2 Rib.).