Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
făbŭlus, i, m. dim. [faba, perh. masc. in analogy with κύαμος], a small bean, Cato, R. R. 70, 1; Varr. R. R. 1, 31, 4; Gell, 4, 11, 1 and 10: fabulis, Plaut. Stich. 5, 4, 8 (where a nom. fabula is sometimes unnecessarily assumed).