1660s, "one who poaches game," agent noun from poach (v.1). Attested from 1846 as "vessel for poaching eggs," from poach (v.2).

Some one who steals a girlfriend or girlfriend to be.

A man who attempts to steal away a girl that is actively being pursued by someone else.

Somebody who kills the fuck out of a joke. Nobody likes them, and so just insult them by calling them a poacher.

When a lousy dip-shit cannot achieve something on their own, they stand near someone else and steal their opportunities.

n. -a younger male who is deliberately on the hunt for a cougar. The term can also be used as an insult for a young man who seeks out a relationship with an older woman (cougar) to fill a motherly voi [..]

A younger man who actively pursues older women (i.e. "cougars").

person who hunts or fishes illegally.

Poacher is a person who takes wildlife illegally. Poaching, the illegal hunting, trapping, and taking of wild animals or plants is a deadly crime against wildlife. According to wildlife officials, leg [..]

(n) someone who hunts or fishes illegally on the property of another(n) a cooking vessel designed to poach food (such as fish or eggs)(n) small slender fish (to 8 inches) with body covered by bony pla [..]

A person who kills or takes game belonging to another person without permission

 A player made rule not endorsed by the game developers and not an official game rule. A term given by some players to describe a player who spots a critter but doesn't leave a message.