Source : Webster's Revised Unabridged Dictionary (1913)

Stag \Stag\, n. [Icel. steggr the male of several animals; or a
   doubtful AS. stagga. Cf. {Steg}.]
   1. (Zo["o]l.)
      (a) The adult male of the red deer ({Cervus elaphus}), a
          large European species closely related to the American
          elk, or wapiti.
      (b) The male of certain other species of large deer.

   2. A colt, or filly; also, a romping girl. [Prov. Eng.]

   3. A castrated bull; -- called also {bull stag}, and {bull
      seg}. See the Note under {Ox}.

   4. (Stock Exchange)
      (a) An outside irregular dealer in stocks, who is not a
          member of the exchange. [Cant]
      (b) One who applies for the allotment of shares in new
          projects, with a view to sell immediately at a
          premium, and not to hold the stock. [Cant]

   5. (Zo["o]l.) The European wren. [Prov. Eng.]

   {Stag beetle} (Zo["o]l.), any one of numerous species of
      lamellicorn beetles belonging to {Lucanus} and allied
      genera, especially {L. cervus} of Europe and {L. dama} of
      the United States. The mandibles are large and branched,
      or forked, whence the name. The lava feeds on the rotten
      wood of dead trees. Called also {horned bug}, and {horse
      beetle}.

   {Stag dance}, a dance by men only. [slang, U.S.]

   {Stag hog} (Zo["o]l.), the babiroussa.

   {Stag-horn coral} (Zo["o]l.), any one of several species of
      large branching corals of the genus {Madrepora}, which
      somewhat resemble the antlers of the stag, especially
      {Madrepora cervicornis}, and {M. palmata}, of Florida and
      the West Indies.

   {Stag-horn fern} (Bot.), an Australian and West African fern
      ({Platycerium alcicorne}) having the large fronds branched
      like a stag's horns; also, any species of the same genus.
      

   {Stag-horn sumac} (Bot.), a common American shrub ({Rhus
      typhina}) having densely velvety branchlets. See {Sumac}.
      

   {Stag party}, a party consisting of men only. [Slang, U. S.]
      

   {Stag tick} (Zo["o]l.), a parasitic dipterous insect of the
      family {Hippoboscid[ae]}, which lives upon the stag and in
      usually wingless. The same species lives also upon the
      European grouse, but in that case has wings.

Stag \Stag\, v. i. (Com.)
   To act as a ``stag'', or irregular dealer in stocks. [Cant]

Stag \Stag\, v. t.
   To watch; to dog, or keep track of. [Prov. Eng. or Slang]
   --H. Kingsley.

Source : WordNet®

stag
     v 1: attend a dance or a party without a female companion
     2: give away information about somebody; "He told on his
        classmate who had cheated on the exam" [syn: {denounce}, {tell
        on}, {betray}, {give away}, {rat}, {grass}, {shit}, {shop},
         {snitch}]
     3: watch, observe, or inquire secretly [syn: {spy}, {snoop}, {sleuth}]

stag
     n 1: male red deer [syn: {hart}]
     2: adult male deer