Owl sound is amusing (4)

I believe the answer is:

hoot

I'm a little stuck... Click here to teach me more about this clue!

'owl sound' is the definition.
(I've seen this in another clue)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for hoot that I've seen before include "Hollow cry" , "Owl's cry" , "Cry of owl" , "On (a ship/train/plane)" , "what's voiced in parliament?" .)

I've seen this clue in The Mirror.

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