c.1600, "to clear out the chest or lungs," from Latin expectoratus, past participle of expectorare "scorn, expel from the mind," literally "make a clean breast," from ex- "out" (see ex-) + pectus (genitive pectoris) "breast" (see pectoral (adj.)). Use as a euphemism for "spit" is first recorded 1827. Original sense in expectorant. Related: Expectorated; expectorating.
expectorate ex·pec·to·rate (ĭk-spěk'tə-rāt')
v. ex·pec·to·rat·ed, ex·pec·to·rat·ing, ex·pec·to·rates
To eject saliva, mucus, or other body fluid from the mouth; spit.
To clear out the chest and lungs by coughing up and spitting out matter.