Dear horn sounds (5)

I believe the answer is:

toots

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

'horn sounds' is the definition.
(I've seen this in another clue)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for toots that I've seen before include "Sounds alarm as motorist" , "sounds horny" , "Florence Dombey's admirer" , "ducks" , "Beeps" .)

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