Underdog
A person or hand who is not mathematically favored to win a pot. For instance, if you flop four cards to your flush, you are not quite a 2:1 underdog to make your flush by the river (that is, you will make your flush about one in three times).
V
Video Poker Machine
The use of a video display to simulate the real game of poker, bearing in mind one is playing a machine and not real players. There are literally hundreds of models of Video Poker Machine. Broadly, these may be categorized into the types: Jacks or Better, Bonus Poker - bigger payoffs for certain hands, Wild Card Games like Deuces Wild and Joker Poker. By law, the Payoff Table listing the payout for each winning hand must be posted on each machine. Also by law, each machine must operate by drawing randomly from one deck of cards.

W
Wild or Wild Card
A card that may be used to substitute for any other card in the deck, such as a deuce in Deuces Wild Video Poker.
Wild Royal
A wild card to make a royal flush.
Winning Hand
A winning hand is one that you get paid for. For most video poker games the lowest winning hand is a Pair of Jacks. In Deuces Wild Video Poker, it's Three of a Kind.