noun

• (archaic) Cotton, or cotton wool.
  "SURBATING; a Diſtemper in a Horſe, who is ſaid to be ſurbated, when the Sole is worn, bruiſed or ſpoiled by travelling without Shoes, or with ill ſhoeing: [...] take Frankincenſe, and rolling it in a little fine Cotton Wool or Bombaſt, with a hot Iron melt it into the Foot betwixt the Shoe and the Toe, until the Orifice, where the Blood was taken away, is fill'd up; [...]"
• (archaic) Cotton, or any soft, fibrous material, used as stuffing for garments; stuffing, padding.
  "[C]ertayne I am there was neuer any kinde of apparell euer inuented, that could more diſproportion the body of man, then theſe Dublettes with great bellies hanging downe beneath their Pudenda, (as I haue ſayd) & ſtuffed with foure, fiue, or ſixe pound of Bombaſt at the least: [...]"
• (figurative) High-sounding words; language above the dignity of the occasion; a pompous or ostentatious manner of writing or speaking.
  "Bombaſt and Buffoonry, by Nature lofty and light, ſoar higheſt of all, [...]"