noun

• Senses relating to animals.
  "I ſhall call this bird the painted vulture. […] the head and neck bare of feathers nearly down to the ſtomach, when the feathers begin to cover the ſkin, and ſoon become long and of a ſoft texture, forming a ruff or tippet, in which the bird by contracting his neck can hide that as well as his head: […]"
• Senses relating to animals.
  "The Afghan urial, which is smaller than the Transcaspian urial, is found in the mountains near Iran's eastern frontier, and is the wild sheep of Afghanistan and western Pakistan. Its ruff is black sprinkled with white hairs and its bib is white."
• (engineering) A collar on a shaft or other piece to prevent endwise motion.
  "The stroke of the cut-off valves is very short, and the ruffs on the parts, g, g, regulate its length."
• (obsolete) An exhibition of haughtiness or pride.
  "Nay, how many Emperours and Princes, that in the Ruff of all their Glory have been taken down from the Head of a Conquering Army, to the Wheel of the Victor's Chariot?"

verb

• (transitive) To shape (fabric, etc.) into a ruff; to adorn (a garment, etc.) with a ruff.
  "The Ladies too were carp’d at, and their Dreſs, / He wants ’em all ruff’d up like good Queen Beſs!"
• (transitive, falconry) Of a falcon, hawk, etc.: to hit (the prey) without fixing or grabbing hold of it.
  "Instantly the keen-eyed hawk "stooped," or descended, with a rushing swoop, and struck one of the birds with her claws, but without killing it, which is called "rifling," or "ruffing" it."
• (rare, transitive) To ruffle; to disorder.
  "Thenceforth the fether in her lofty creſt, / Ruffed of loue, gan lowly to auaile, / And her prowd portaunce, and her princely geſt, / VVith which ſhe earſt tryumphed, now did quaile: […]"
• (obsolete, transitive) Of a bird: to ruffle its feathers.
  ""Scat," the crow said. I ignored him. He ruffed up his feathers, doubling his size."

noun

• (obsolete) A bottom-dwelling carnivorous fish of the family Sparidae found in temperate and tropical waters; a porgy or sea bream.
  "A Ruff, or Sea-bream. Melanurus."

verb

• (ambitransitive) To play a trump card to a trick when unable to follow suit (that is, when unable to play a card of the same suit as the previous or leading card).
  "Zia [Mahmood] ruffed the club return and then played the ace of hearts and a heart, leaving declarer with another spade loser for two down."
• (transitive) Especially in the form ruff out: to defeat (a card, etc.) by ruffing, thus establishing the master card in the suit led.
  "Then I played on diamonds, to ruff out the suit – but East had four diamonds and West none, so I had annoyingly to lose a trick to East's ♣K in the end."