They wriggle in a creel sometimes (4)
I believe the answer is:
eels
'they wriggle' is the definition.
Although both the answer and 'wriggle' are nouns, they are not in the same form of the noun.
'in a creel sometimes' is the wordplay.
'in' indicates a hidden word.
'EELS' is hidden within 'creel sometimes'.
Can you help me to learn more?
(Other definitions for eels that I've seen before include "Else (anag.)" , "Sea creatures found in lees" , "Snakes wriggling in lees" , "Odd fish found in the lees" , "They have long bodies and very small fins" .)