Steer clear of Donald! (4)
I believe the answer is:
duck
I believe this clue is a double definition.
'steer clear' is the first definition.
(I've seen this before)
'donald' is the second definition.
(donald duck is a cartoon character)
'of' acts as a link.
(Other definitions for duck that I've seen before include "Zero runs; bird" , "Water bird - get out of the way" , "Water bird; zero score" , "Steer clear" , "Use one's wits to get something" .)