Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
mūcus (mucc-), i, m. [mug, mungo; cf. also Sanscr. muć, solvere, dimittere], snivel, mucus of the nose: mucusque, et mala pituita nasi, Cat. 23, 17; Cels. 4, 18.