Source : Webster's Revised Unabridged Dictionary (1913)

Dephlegm \De*phlegm"\, v. t. [Pref. de- + phlegm water; cf. F.
   d['e]phlegmer, d['e]flegmer.] (O. Chem.)
   To rid of phlegm or water; to dephlegmate. [Obs.] --Boyle.