Instinctive (3)
'instinctive' is the definition.
(I know that instinctive can be written as natural)
This is the entire clue.
(Other definitions for natural that I've seen before include "Unaffected; unaltered" , "as one might expect" , "Expected - appropriate - artless" , "Everyday" , "One regarded as sure to succeed in some field" .)
'instinctive' is the definition.
(as in a gut feeling)
This is all the clue.
(Other definitions for gut that I've seen before include "Stomach, belly" , "Thread made from animal intestines" , "Part of intestine" , "Food processor" , "spare tyre" .)