Puckering up foolishly, grins fatuously (7)

I believe the answer is:

pursing

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

'puckering up foolishly grins fatuously' is the definition.
I can't judge whether this defines the answer.

'puckering up foolishly grins' is the wordplay.
'puckering up' becomes 'pu' (this could be a standard abbreviation I've not previously seen).
'foolishly' is an anagram indicator.
'grins' with letters rearranged gives 'rsing'.
'pu'+'rsing'='PURSING'

Can you help me to learn more?

I've seen this clue in the Evening Standard.

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.