noun

• (by extension) The polishing head of a power buffer, often made of wool.
  "Make sure that the power buffer's lamb's-wool bonnet is clean. Change or rinse the bonnet frequently to avoid scratching the finish. Use the bonnet as a mitten to buff in the crevices and other areas that the power buffer can't reach."
• (Australia, British, New Zealand, South Africa, Commonwealth, automotive) The hinged cover over the engine of a motor car, also known as a hood in chiefly Canada and the US.
  "The car is burgundy red, wide and elegant, ten years old but still the boys are impressed and they run to touch it, pressing sticky handprints against the polished bodywork and trying to climb up onto the bonnet."
• (nautical) A length of canvas attached to a fore-and-aft sail to increase the pulling power.
  "And standing along to the Westward, this night we tryed with our mayne coarse and bonnet. On Saturday night we came to an anker, in three fathomes against Sewramo."
• (obsolete, slang) An accomplice of a gambler, auctioneer, etc., who entices others to bet or to bid.

verb

• (transitive) To put a bonnet on.
• (obsolete) To take off the bonnet or cap as a mark of respect; to uncover.
  "Hee hath deſerued worthily of his Countrey, and his aſſent is not by ſuch eaſie degrees as thoſe, who hauing beene ſupple and courteous to the People, Bonnetted, without any further deed, to haue them at all into their eſtimation, and report:"
• (dated, transitive) To pull the bonnet or cap down over the eyes of.
  "“You’re a dutiful and affectionate little boy, you are, ain’t you?” said Mr. Weller, “to come a bonnetin’ your father in his old age?”"