Toot one's own horn? (4)
I believe the answer is:
honk
'toot one's own horn?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for honk that I've seen before include "Cry of the wild goose" , "Toot one's horn" , "Cry of a goose - sound of a horn" , "Toot of a horn - cry of a goose - smell nasty" .)