Off colour
British english - someone who is looking pale, not their usual colour. To mean someone who is feeling unwell, "not themselves" or their "usual self" on that day. Can also be a team or department not performing to their usual standard.
"Are you alright? You look a bit off colour"
"The team played off colour today"
"The team played off colour today"
Feeling off colour
You're feeling off colour when there's something wrong with your health even though it's nothing to worry about.
John:"I'm feeling off colour today, it's nothing serious but something's not quite right"
John's mum:"Well, you shouldn't go to school then. I'll call the doctor".
John's mum:"Well, you shouldn't go to school then. I'll call the doctor".
gone off food colouring
When you leave food coloring out too long and it goes all modly and staly.
The gone off food colouring tastes like piss.