Watch as Rob's nerve starts to fail (7)

I believe the answer is:

observe

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

'watch' is the definition.
(I know that watch can be written as observe)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for observe that I've seen before include "Keep - watch" , "Verbose (anag.)" , "Obverse (anag.)" , "monitor" , "Notice, perceive" .)

I've seen this clue in the Sydney Morning Herald.

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.