Has a quietening effect, which puzzles one (7)

I believe the answer is:

baffles

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

'puzzles one' is the definition.
'baffles' can be an answer for 'puzzles' ('baffle' can be a synonym of 'puzzle'). I am not sure about the 'one' bit.

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Another definition for baffles that I've seen is " Bewilders, flummoxes".)

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.