Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
quĕrŭlōsus (quĕrēl-), a, um, adj. [querulus], full of complaints, querulous (late Lat.): murmuratores, Vulg. Ep. Jud. v. 16; Cassiod. Var. 9, 14.