A person who spits or something that gobbles; in British slang, someone who spits or makes a mess with their mouth.
From 'gob' (mouth, or to spit) + '-er' (one who does). 'Gob' likely comes from Middle Irish 'gob' meaning mouth, and entered British English slang centuries ago.
'Gobber' shows how the same '-er' suffix that creates 'teacher' (one who teaches) and 'baker' (one who bakes) can also create insulting words—it's the same grammar pattern, but context makes all the difference in tone.
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