Slender swimmer has some feeling (3)
I believe the answer is:
eel
'slender swimmer' is the definition.
(I've seen this in another clue)
'some feeling' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'EEL' can be found hidden inside 'feeling'.
'has' is the link.
(Other definitions for eel that I've seen before include "Slippery type" , "Evasive type" , "Slender fish" , "elusive person" , "Slimy fish" .)