cold as a mackerel adjective2 •Very cold (in temperature, emotionally, etc.).“I tell you, Governor, that in those days they weren’t ashamed to have a little good liquor around to warm the insides of a man weary and as cold as a mackerel from an all night job.” — 1920 •Completely unconscious.She had just slid forward in a pile in front of the chair, on top of her nice hat. She was as cold as a mackerel. — 1942
