"Simpsons” bus driver (4)
I believe the answer is:
otto
'simpsons bus driver' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for otto that I've seen before include "Male German name - a palindrome" , "- - Preminger (films)" , "Reversible German" , "German emperor" , "____ Preminger, US film director born in Austria" .)