Fig. to drink alcohol excessively; to be in the habit of drinking alcohol excessively. Jeff really drank like a fish at the party on Saturday.I worry about Nancy; she drinks like a fish.
Consume large amounts of alcoholic beverages, as in He always drinks like a fish at holiday dinners. The expression, first recorded in the mid-1600s, alludes to the way fish obtain oxygen, which causes them to be open-mouthed and appear to be constantly drinking.