Crossword Genius

Finish - a sentence? (3,1,4,2)

Ross

I believe the answer is:

put a stop to

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

'sentence?' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'finish a' is the wordplay.
I cannot really understand how this works, but
'finish' could be 'stop' (synonyms) and 'stop' is found in the answer.
'a' is found in the answer.
The remaining letters 'putto' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...

Can you help me to learn more?

(Another definition for put a stop to that I've seen is " Cause to end".)

I've seen this clue in The Globe and Mail.
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