Peer must have some noble qualities (5)
I believe the answer is:
equal
'peer' is the definition.
(I know that peer can be written as equal)
'some noble qualities' is the wordplay.
'some' indicates the answer is hidden within the clue (some parts of the word are used).
'EQUAL' can be found hidden inside 'noble qualities'.
'must have' acts as a link.
(Other definitions for equal that I've seen before include "The same in all aspects" , "Alike" , "Commensurate" , "Identical, add up to" , "On a par" .)