Head sliced off, jiggle fish (4)
I believe the answer is:
hake
'fish' is the definition.
(I know that hake is a type of fish)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for hake that I've seen before include "Common food fish" , "Food fish; rhymes with create" , "Cod-like fish" , "Type of fish" , "Swimmer" .)