Gentlemen in suits. Tops! (7)

I believe the answer is:

summits

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

'tops' is the definition.
(I know this)

'gentlemen in suits' is the wordplay.
'gentlemen' becomes 'mm' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'mm' put inside 'suits' is 'SUMMITS'.

Can you help me to learn more?

(Another definition for summits that I've seen is " tops".)

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.