Swimmer shaken when embraced by the Poles (4)

I believe the answer is:

hake

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

'swimmer' is the definition.
(type of fish)

'shaken when embraced by the poles' is the wordplay.
'HAKE' is hidden within the letters.
However, I'm unsure how the hidden word is indicated.

Can you help me to learn more?

(Other definitions for hake that I've seen before include "Food fish; rhymes with create" , "Cod-like fish" , "Common food fish" , "Type of fish" , "Swimmer" .)

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.