Being ready to take action in school with a rash (12)

I believe the answer is:

preparedness

I'm a little stuck... Click here to teach me more about this clue!

But I can't explain it at all! Could you help me understand?

(Another definition for preparedness that I've seen is " State of readiness".)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.