(PW) be afraid at the last minute, lose confidence

I was prepared to make a speech, but I got cold feet when I saw how many people were going to hear it.

(free)

pl.n. Slang

Fearfulness or timidity preventing the completion of a course of action.

pl n

Informal loss or lack of courage or confidence

(UsingEnglish)

If you get cold feet about something, you lose the courage to do it.

(dictionary) noun Informal .

a loss or lack of courage or confidence; an onset of uncertainty or fear:

She got cold feet when asked to sing a solo.