noun / verb
honk
HAHNK/hˈɑŋk/
A loud nasal sound, or making such a sound.
He honks the bicycle horn, making the nearby listener cover one ear.

Etymology
Honk began as an imitation of a goose’s cry. Its use for sounding a horn extends that loud, nasal animal sound to a mechanical one.
In context
She's in the rental car and I leave her parked on the side of the road. Hey, let me know honk if a cop's coming.