close quarters (n.)

1722, originally nautical, also close-fights, "bulkheads fore and aft for men to stand behind in close engagements to fire on the enemy," it reflects the confusion of close (v.) and close (adj.); "now understood of proximity, but orig. 'closed' space on ship-board where last stand could be made against boarders" [Weekley]. Compare also closed-minded (1880s), a variant of close-minded, as if "shut" rather than "tight," also closed-fisted, occasional variant of close-fisted "stingy."