Sounds the horn, sweetheart (5)

I believe the answer is:

toots

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'sounds' is the definition.
(toot is a kind of sound)

I cannot understand how the remainder of the clue works.

(Other definitions for toots that I've seen before include "Florence Dombey's admirer" , "ducks" , "Horn sounds - honey" , "gentle Dickensian" , "Beeps" .)

I've seen this clue in the Evening Standard.

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