The Collaborative International Dictionary of English v.0.48:

Poach \Poach\ (p[=o]ch), v. t. [imp. & p. p. Poached
   (p[=o]cht); p. pr. & vb. n. Poaching.] [F. pocher to place
   in a pocket, to poach eggs (the yolk of the egg being as it
   were pouched in the white), from poche pocket, pouch. See
   Pouch, v. & n.]
   1. To cook, as eggs, by breaking them into boiling water;
      also, to cook with butter after breaking in a vessel.
      --Bacon.
      [1913 Webster]

   2. To rob of game; to pocket and convey away by stealth, as
      game; hence, to plunder. --Garth.
      [1913 Webster]

WordNet (r) 3.0 (2006):

poaching
    n 1: cooking in simmering liquid

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "poaching":
   abstraction, annexation, appropriation, baking, barbecuing,
   basting, boiling, boosting, braising, brewing, broil, broiling,
   catering, conversion, conveyance, cookery, cooking, cuisine,
   culinary science, domestic science, embezzlement, filching, fraud,
   frying, graft, grilling, home economics, liberation, lifting,
   nutrition, pan-broiling, pilferage, pilfering, pinching, roasting,
   sauteing, scrounging, searing, shirring, shoplifting, simmering,
   snatching, sneak thievery, snitching, stealage, stealing, steeping,
   stewing, swindle, swiping, theft, thievery, thieving, toasting