Tropical tern (5)
I believe the answer is:
noddy
'tropical tern' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for noddy that I've seen before include "Old fool" , "Enid Blyton hero" , "Big Ears' friend" , "Nineteen [TWIT]" , "Blyton character - tern" .)