A part below is broken (5)
I believe the answer is:
elbow
'a part' is the definition.
(elbow is a kind of part)
'below is broken' is the wordplay.
'is broken' indicates an anagram.
'below' anagrammed gives 'ELBOW'.
(Other definitions for elbow that I've seen before include "part of the body" , "Nudge" , "given to one about to leave" , "Major arm joint" , "Sharp bend in a road or river" .)