Singer — cor, awful one, right? (7)
I believe the answer is:
crooner
'singer' is the definition.
(I know that crooner is a type of singer)
'cor awful one right?' is the wordplay.
'awful' indicates an anagram.
'right?' becomes 'r' (abbreviation).
'cor' anagrammed gives 'cro'.
'cro'+'one'+'r'='CROONER'
(Other definitions for crooner that I've seen before include "Crosby or Sinatra?" , "Singer like Bing and Frank" , "Profession of Bing, Frank or Perry" , "One who sings like Bing?" , "Crosby-type singer" .)