Stud may enter this noble order of chivalry (7)
I believe the answer is:
earlobe
'stud may enter this' is the definition.
The definition suggests a singular noun which matches the answer.
'noble order of chivalry' is the wordplay.
I cannot quite understand how this works, but
'noble' could be 'earl' (earl is a kind of noble) and 'earl' is found within the answer.
'order' could be 'obe' (Order of the British Empire award) and 'obe' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for earlobe that I've seen before include "that could have a ring to it" , "place to hang jewelry" , "Fleshy part of hearing organ" , "Part of body" , "It depends on the listener" .)