Made a short, clear sound on a horn or whistle, or bragged or boasted about something.
From Old English or possibly imitative (mimicking the sound itself). The 'bragging' meaning emerged in the 1800s from 'tooting one's own horn' (publicly celebrating yourself).
The phrase 'toot your own horn' comes from parade traditions—horns announced important people, so literally tooting for yourself seemed immodest, which is why self-promotion still feels rude in many cultures.
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