Idiot singer's third to do a turn (4)
I believe the answer is:
bozo
'idiot' is the definition.
(I've seen this in another clue)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for bozo that I've seen before include "Clot" , "twit" , "Incompetent fool (US)" , "Stupid man (US)" , "Dimwit" .)