Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† phlegma (flegma), ătis, n., = φλεγμα, a clammy humor of the body, phlegm (post-class.): flegma dissolvere, Pall. 8, 6, 1; Veg. Vet. 3, 19; Hier. Ep. 52, 6; Isid. 4, 7, 29.