Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
grăcĭlentus, a, um, adj. [gracilis], slender, thin (ante- and post-class. for the usual gracilis): filum, Enn. ap. Non. 116, 8 (Ann. v. 259 Vahl.): equus, Gell. 4, 12, 2.