Joint push (5)
I believe the answer is:
elbow
I believe this clue is a double definition.
'joint' is the first definition.
(elbow joint is a kind of joint)
'push' is the second definition.
(thesaurus)
(Other definitions for elbow that I've seen before include "Below (anag.)" , "Dismissal?" , "Jostle" , "Barge" , "Limb hinge" .)