A person who fishes for or catches haddock, or a boat/vessel used in haddock fishing.
From 'haddock' (a type of fish) plus the agent suffix '-er' (one who does something). This occupational term emerged with commercial fishing industries.
Haddock was so economically important to North Atlantic communities that fishermen had specific names for their trades—a 'haddocker' was a specialized profession, not just a generic fisherman.
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