Upper arm bone (7)
I believe the answer is:
humerus
'upper arm bone' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for humerus that I've seen before include "Arm bone (that sounds comical)" , "Bone that sounds funny?" , "Boneo of the upper arm" , "What's often thought funny" , "Upper arm bone" .)