have (or show) a lot of bottle have (or show) boldness or initiative. British informal
☞ Bottle in the sense 'courage, nerve' comes from bottle and glass. That is rhyming slang for arse, which itself came in 20th-century British slang to mean 'courage'. So if you have lost your bottle (in effect, 'lost your arse'), or your bottle has fallen out, your courage has failed you. The derived verb bottle out (or bottle it) means 'fail to do something as a result of losing your nerve'.