Yours, Etc.: Origins and Uses of 8 Sign-Offs
1782, from Latin expectorantem (nominative expectorans), present participle of expectorare (see expectorate). From 1811 as an adjective.
expectorant ex·pec·to·rant (ĭk-spěk'tər-ənt)adj. Promoting or facilitating the secretion or expulsion of phlegm, mucus, or other matter from the respiratory tract. n. An expectorant medicine.