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 icecream. I dont like to eat icecream very often. 2. Feeling blue to feel sad or depressed; feeling down. Last week my cat died, Im 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 youre trying to convince smb of smth, arguing with smb but youre not willing to over. Ive been arguing with my friend for 5 hours until I was blue in my face but he just wasnt listening to me. 5. Boys in blue the police. The boys in blue came and stopped the robbery.