The Idiom Attic - a collection of hundreds of English idioms, each one explained.
"military" idioms...
See also, a list of phrases that relate in some way to the word military
" About face "
Meaning:
1. A military command to turn when on parade. 2. A change from one’s previous position.
Example:
1. Stand to attention! Present arms! About face! 2. Winston Churchill joined parliament as a Conservative and then did an about face and changed to the Liberals, before going about face again and re-joining the Conservatives.
Someone who is unpredictable and can cause damage by being reckless.
Example:
These negotiations with the Chinese are at a critical stage. Keep Jack out of it, he's just the sort of loose cannon that would say the wrong thing and upset them.