Stiffener making a funny sound (7)
I believe the answer is:
humerus
'stiffener' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'a funny sound' is the wordplay.
'a funny' becomes 'humorous' (I've seen this before).
'sound' shows a homophone (sound like).
'humorous' is a homophone of 'HUMERUS'.
'making' is the link.
Can you help me to learn more?
(Other definitions for humerus that I've seen before include "Bone from shoulder to elbow" , "Upper-arm bone" , "Arm bone (that sounds comical)" , "Boneo of the upper arm" , "Arm bone - the "funny bone"" .)