Dole out a penalty on return (5)

I believe the answer is:

allot

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

'dole out' is the definition.
(synonyms)

'a penalty on return' is the wordplay.
'penalty' becomes 'toll' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on return' is a reversal indicator.
'toll' in reverse letter order is 'llot'.
'a'+'llot'='ALLOT'

Can you help me to learn more?

(Other definitions for allot that I've seen before include "Apportion (something to someone)" , "Assign a share" , "Apportion, share" , "Dish out" , "Dispense or distribute" .)

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.