ruff

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A stiffly starched frilled or pleated circular collar of lace, muslin, or other fine fabric, worn by men and women in the 1500s and 1600s.
• noun A distinctive collarlike projection around the neck, as of feathers on a bird or of fur on a mammal.
• noun A migratory sandpiper (Philomachus pugnax) of the Eastern Hemisphere, the male of which has collarlike, erectile feathers around the neck during the breeding season.
• noun The playing of a trump card when one cannot follow suit.
• noun An old game resembling whist.
• transitive & intransitive verb To trump or play a trump.
• noun Any of several marine fishes of the family Centrolophidae, usually having spiny dorsal fins.
• noun A small edible fish (Arripis georgianus) of coastal and estuarine waters of southern Australia.

from The Century Dictionary.

• To plait, pucker, or wrinkle; draw up in plaits or folds.
• . To ruffle; disorder.
• In falconry, to hit without trussing.
• To applaud by making a noise with hands or feet. [Scotch.]
• In card-playing, to trump when holding none of the suit led.
• Also, erroneously, rough.
• To heckle (flax) on a coarse heckle called a ruffer.
• In hat-manuf., to nap.
• noun A large integumental fold surrounding the base of the foot of Haliotis, the ear-shell.
• noun The bird Pavoncella or Machetes pugnax (the female of which is called a reeve), a kind of sandpiper belonging to the family Scolopacidæ, having in breeding-plumage an enormous frill or ruff of feathers of peculiar texture on the neck, and noted for its pugnacity.
• noun An old game at cards, the predecessor of whist.
• noun In card-playing, the act of trumping when the player has no cards of the suit led.
• noun An obsolete form of rough.
• noun A dialectal form of roof.
• Same as rough.
• noun A state of roughness; ruggedness; hence, rude or riotous procedure or conduct.
• noun A projecting band or frill, plaited or bristling, especially one worn around the neck.
• noun Something resembling a ruff in form or position.
• noun The loose top of the boot worn in the seventeenth century turned over and made somewhat ornamental: same as boot-top, 2 . Sometimes the top was of a different leather from the rest of the boot. Spanish leather is especially mentioned, and the edge was sometimes ornamented with gold lace or similar passement.
• noun In machinery, an annular ridge formed on a shaft or other piece, commonly at a journal, to prevent motion endwise. Thus, in the cut, a, a are ruffs limiting the length of the journal b, to which the pillows or brasses are exactly fitted, so that the shaft is prevented from moving on end. Ruffs sometimes consist of separate rings fixed in the positions intended by set-screws, etc. They are then called loose ruffs.
• noun . Figuratively, that which is outspread or made public; an open display; a public exhibition, generally marked by pride or vanity.
• noun A breed of domestic pigeons; a kind of Jacobin having a ruff.
• noun Accrina or Gymnocephalus cernua, a fish of the family Percidæ, distinguished by the muciferous channels of the head, the villiform teeth of the jaws, and the connected dorsal fins.
• noun A Victorian fish, Arripis georgianus, of the family Percidæ. A. salar is the Australian fish called salmon or salmon-trout. See salmon, 3 .
• noun A low vibrating beat of a drum; a ruffie. See ruffle.

from the GNU version of the Collaborative International Dictionary of English.

• verb (Card Playing) To trump.
• transitive verb To ruffle; to disorder.
• transitive verb (Mil.) To beat with the ruff or ruffle, as a drum.
• transitive verb (Hawking) To hit, as the prey, without fixing it.
• transitive verb (Card Playing) To play a trump card at bridge.
• noun A muslin or linen collar plaited, crimped, or fluted, worn formerly by both sexes, now only by women and children.
• noun Something formed with plaits or flutings, like the collar of this name.
• noun An exhibition of pride or haughtiness.
• noun obsolete Wanton or tumultuous procedure or conduct.
• noun (Mil.) A low, vibrating beat of a drum, not so loud as a roll; a ruffle.
• noun (Mach.) A collar on a shaft ot other piece to prevent endwise motion. See Illust. of Collar.
• noun (Zoöl.) A set of lengthened or otherwise modified feathers round, or on, the neck of a bird.
• noun A limicoline bird of Europe and Asia (Pavoncella pugnax, syn. Philomachus pugnax) allied to the sandpipers. The males during the breeding season have a large ruff of erectile feathers, variable in their colors, on the neck, and yellowish naked tubercles on the face. They are polygamous, and are noted for their pugnacity in the breeding season. The female is called reeve, or rheeve.
• noun A variety of the domestic pigeon, having a ruff of its neck.