The Whiner
Chatbox-whining players are different than the above. People who whine in public, to a group of strangers who couldn't care less, are very likely used to whining. In other words, a whiner is not likely to be on tilt when losing. A variation of The Whiner is he who whines "let's play head-up" any time someone beats him two hands in a row, or three of so ugly hands in an hour. Both these types are serious, long-term losers.
U
center potThe main pot in a table stakes game where one or more players are all in.U
double-ace flushUnder unconventional rules, a flush with one or more wild cards in which they play as aces, even if an ace is already present.U
dealer's choiceA version of poker in which the deal passes each game and each dealer can choose, or invent, a new poker game each hand or orbit.U
walkA walk is the situation where all players fold to the big blind.U
slow playSee slow play (poker). Also "sandbag".U
Weak is Strong or Strong is WeakIn its most simplistic form, this usually applies to novice players but frequently applies to pros as well. Basically, players like to be actors, and when they have a monster hand they tend to look disinterested. For example: "Oh, is it my turn to act" or "Oh I guess I will play these cards". Alternatively, a player increasing the level of his voice while raising the pot, and trying to look intimidating.. may be running a bluff.U
stakesThe definition of the amount one buys in for and can bet. For example, a "low stakes" game might be a $10 buy-in with a $1 maximum raise.U
The Rant

Many online poker tells are the result of bad players telling you that they are about to play even worse than normal. How nice of them. The most obvious of these announcements is The Rant. Flawed players go on tilt in all sorts of poker games, and online is no exception. The thing about online is loudmouths and bullies can't glare at, roll their eyes or do some other belittling physical action. But via the chatbox they CAN insult their opponents. They can't say "change the deck" but they can rant about software being rigged against their genius-level play.

Boiling it down to the basics, a player who goes on a rant about stupid opponents or rigged software might just as well paint themselves purple with ten inch letters: "I am on tilt". Besides obviously horrible opponents, ranters are THE players to target in any game, even more so than obvious multi-tablers. You want to play against people on tilt, but you also want to be sure you don't take them off tilt by playing a weak hand at them that helps them to calm down. Go ahead and goad abusive players in the chatbox. These are almost always players who think they are far better than they are, and play considerably worse when losing than when winning. They will often make the game. Treasure the ranters. To a large degree, winning poker is about defeating people who act stupidly. Ranters are at the top of the list.

N
limp, limp inTo enter a pot by simply calling instead of raising.U
darkDescribing an action taken before receiving information to which the player would normally be entitled. I'm drawing three, and I check in the dark. Compare to "blind".U