Idioms in English - ’Blue’

Colour idioms (Blue) 1. Once in a blue moon – smth rarely happens, not very often. I visit my sister once in a blue moon. Once in a blue moon I have some ice-cream. I don’t like to eat ice-cream very often. 2. Feeling blue – to feel sad or depressed; feeling down. Last week my cat died, I’m feeling blue. 3. Out of the blue – when smth surprises you, coming from nowhere. I was driving down the road and this car swerved in front of me out of the blue. 4. Blue in the face – when you’re trying to convince smb of smth, arguing with smb but you’re not willing to over. I’ve been arguing with my friend for 5 hours until I was blue in my face but he just wasn’t listening to me. 5. Boys in blue – the police. The boys in blue came and stopped the robbery.