1601, "to clear out the chest or lungs," from L. expectoratus, pp. of expectore "scorn, expel from the mind," lit. "make a clean breast," from ex- "out" + pectus (gen. pectoris) "breast." Use as a euphemism for "spit" is first recorded 1827. Original sense in expectorant (1811).
Main Entry: ex·pec·to·rate Pronunciation: -t&-"rAt Function: verb Inflected Forms: -rat·ed; -rat·ing transitive senses 1: to eject from the throat or lungs by coughing or hawking and spitting 2:SPITexpectorateintransitive senses 1: to discharge matter from the throat or lungs by coughing or hawking and spitting 2:SPIT