Homer Simpson exclamation (3)
I believe the answer is:
doh
'homer simpson exclamation' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for doh that I've seen before include "First note of musical scale" , "annoyed expression" , "Tonic (mus.)" , "First note of tonic sol-fa scale" , "How foolish of me" .)