Sound of a tugboat's horn (4)
I believe the answer is:
toot
(Other definitions for toot that I've seen before include "Sound of a car horn" , "Noise made by car horn" , "honk horn" , "Horn's sound (T, not H)" , "Briefly blow" .)
I believe the answer is:
toot
(Other definitions for toot that I've seen before include "Sound of a car horn" , "Noise made by car horn" , "honk horn" , "Horn's sound (T, not H)" , "Briefly blow" .)