Again pondered about allowing it at last (9)

I believe the answer is:

rethought

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

'allowing it at last' is the definition.
I can't judge whether this definition defines the answer.

'again pondered' is the wordplay.
'again' becomes 're'.
'pondered' becomes 'thought' (I can't justify this - if you can you should give a lot more credence to this answer).
're'+'thought'='RETHOUGHT'

'about' acts as a link.

Can you help me to learn more?

(Other definitions for rethought that I've seen before include "went back to drawing board" , "considered from a new angle" , "Considered afresh" .)

I've seen this clue in The Telegraph.

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.