Sad trombone sound Crossword Clue

 The answer to the crossword clue "sad trombone sound" is WAHWAH. It is a three-letter word that is a brass sound effect that is commonly used to indicate something sad or disappointing. It is often used in cartoons, movies, and TV shows.

Here are some other possible answers to the clue "sad trombone sound":

WAHWAH

BOO

OOF

SAD

DISAPPOINTED

FAIL

I hope this helps!