It's wrong to take a rest! (3)
I believe the answer is:
sit
'a rest' is the definition.
(I've seen this in other clues)
'it's wrong' is the wordplay.
'wrong' indicates an anagram.
'its' is an anagram of 'SIT'.
'to take' acts as a link.
(Other definitions for sit that I've seen before include "Be sedentary" , "Perch" , "Be seated" , "Pose (for artist)" , "Rest on one's haunches" .)