One of the Fab Four (5)
'one of the fab four' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ringo that I've seen before include "One of The Beatles" , "The drumming Beatle" , "Member of group" , "Starr drummer" , "Beatles drummer" .)
(Other definitions for beatle that I've seen before include "John, Paul or George, say" , "eg Ringo" , "Paul, Ringo, John or George" , "One of the famous four pop musicians, says Paul or John" .)