The word 'spurge' entered English in the 14th century from the Old French 'espurge', a noun derived from the verb 'espurgier', meaning 'to purge'. This, in turn, came from the Latin 'expurgare', meaning 'to cleanse out' or 'purge'. The name was given to these plants due to the strong purgative properties of their milky, latex-like sap, which was historically used in medicine. Thus, the modern botanical term retains a direct, functional link to its original Latin meaning related to cleansing or purging.

This word is a simplex form. It is a loanword from Old French, which derived it from Latin.