1. Feeling Blue - feeling unwell
Example : I am feeling blue from last night I think I am having fever.
2. looking off color -looking ill
Example : If someone looks off color means they look ill.
3. in the black - If your bank account is in credit, it is in the black.
4. in the pink - If you are in very good health, you are in the pink.
5. in the red - If your bank account is overdrawn, it is in the red.
6. once in the blue moon - something happens very rarely.
7. pink sleep - If someone receives a pink slip, they receive a letter telling them they have lost their job.
8. red letter day - A red letter day is a one of good luck, when something special happens to you.
9. black sheep - Someone who is the black sheep doesn't fit into a group or family because their behaviour or character is not good enough.