the.com/locker room

means A changing room for athletes or team members — and by extension, the loose, unguarded talk that happens in that private, same-team setting.

from Straightforward compound: 'locker,' from 'lock' (the latching cabinet itself, a 19th-century invention for securing gear), plus 'room.' The phrase 'locker room talk' as shorthand for crude, off-the-record banter is a 20th-century extension — the idea that what's said among teammates behind closed doors, stripped of outside company, wouldn't survive contact with polite air.