verb

• (transitive) To cook (something) in simmering or very hot liquid (usually water; sometimes wine, broth, or otherwise).
  "Eldridge closed the despatch-case with a snap and, rising briskly, walked down the corridor to his solitary table in the dining-car. Mulligatawny soup, poached turbot, roast leg of lamb—the usual railway dinner."
• (intransitive) To be cooked in such manner.
  "The white of an egg with spirit of wine, doth bake the egg into clots, as if it began to poach."

verb

• (ambitransitive) To trespass on another's property to take fish or game.
• (ambitransitive) To take game or fish illegally.
  "A 2016 study using carbon dating of more than 200 tusks from seizures spanning nine countries suggested that illegal ivory originates from elephants poached recently, instead of being pilfered from aging stockpiles kept by various nations."
• (by extension, ambitransitive) To take anything illegally or unfairly.
  "Chelsea's embarrassment was symbolised by Ross Barkley's inexplicable header straight to the feet of Aguero to poach his second and Ilkay Gundogan capped that early blitz with a low drive."
• (figurative) To intrude; to interfere; to get involved inappropriately, without welcome.
  "to poach in foreign academic disciplines"