Character of one who may sing in choir (5)
I believe the answer is:
tenor
I believe this is a double definition.
'character' is the first definition.
(I've seen this in another clue)
'one who may sing in choir' is the second definition.
(type of singing voice)
'of' acts as a link.
(Other definitions for tenor that I've seen before include "One singing" , "Pavarotti, maybe" , "theme" , "Highest male voice" , "thread" .)