This is a quote from Susie Madrak, aka Urban Guerrilla, as posted at Crooks & Liars.
2) Knowing how to sound like you agree with an opposing view while tactfully bringing the opposition around to your way of thinking.
Players play any one of 7 pre-WWI European countries and try to take over the rest. Gameplay can be best described as a cross between Risk and chess. Risk, because of the map-based, multi-player world domination aspect, chess, because the strategies are complex even though the rules may be simple. In addition, like chess, Diplomacy is the only other board game with popularity in the play-by-mail or play-by-email form.
A backstab is often abbreviated as "stab."
Player 2: All is fair in love, war and Diplomacy.