### Clue: Credit (very large) by a crooner? (6)
### Answer: CROSBY 
 ### Explanation: Definition: crooner
  CR(*$$cr$$edit*) OS(*very large*,$$o$$ut$$s$$ize) *BY*.  Defn:  Bing (1903-1977), one of the most successful *crooner*s of the century.  His rendition of Irving Berlin's White Christmas is a perennial favourite.