The Collaborative International Dictionary of English v.0.48:

Chaser \Chas"er\, n.
   1. One who or that which chases; a pursuer; a driver; a
      hunter.
      [1913 Webster]

   2. (Naut.) Same as Chase gun, esp. in terms bow chaser
      and stern chaser. See under Bow, Stern.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chaser \Chas"er\, n.
   1. One who chases or engraves. See 5th Chase, and
      Enchase.
      [1913 Webster]

   2. (Mech.) A tool with several points, used for cutting or
      finishing screw threads, either external or internal, on
      work revolving in a lathe.
      [1913 Webster]

WordNet (r) 3.0 (2006):

chaser
    n 1: a person who is pursuing and trying to overtake or capture;
         "always before he had been able to outwit his pursuers"
         [syn: pursuer, chaser]
    2: a drink to follow immediately after another drink

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "chaser":
   Casanova, Don Juan, Mickey, Mickey Finn, act, afterpiece, aperitif,
   bit, carver, clay modeler, cocktail, curtain, curtain call,
   curtain raiser, divertimento, divertissement, doch-an-dorrach,
   drink, earth artist, epilogue, exode, exodus, expository scene,
   eye-opener, figurer, figuriste, finale, follower, gem carver,
   graver, highball, hoke act, hunter, interlude, intermezzo,
   intermission, introduction, knockout drops, lady-killer, masher,
   mason, mixed drink, modeler, molder, monumental mason, nightcap,
   number, parting cup, philander, philanderer, pousse-cafe, prologue,
   punch, pursuant, pursuer, quester, routine, scene, sculptor,
   sculptress, sculpturer, seeker, shtick, sketch, skit,
   song and dance, stand-up comedy act, statuary, stirrup cup,
   stonecutter, striptease, sundowner, turn, wax modeler,
   wee doch-an-dorrach, womanizer, wood carver