If you read any online poker talk you will see references to these styles.
TAG: Tight Aggressive. A TAG player usually only plays the top 2 or 3 groups of hands, but when they do enter a pot they will bet aggressively preflop and on the flop. TAG tends to be a fairly easy to follow tournament strategy.
LAG: Loose Aggressive. A LAG player will play a much wider range of hands, but will play them all very similar. Raising preflop, and betting flops whether hitting or not. Requires more skill in terms or reading opponent.
Rock: Plays only premium hands, if they come in raising you had better believe they have the goods so if you don’t hit, get out of there. Definitely not the most exciting play to watch, but setting yourself up as a rock does allow you to steal on occasion as opponents give you credit for big hands when you do enter a pot.
Fish: What every poker player wants to see at the table. The fish is the guy that calls down your bets with 4th best pair. The fish lets you catch up and draw out for cheap and generally donates to the cause. The fish is the guy that looks perplexed and doesn’t know that trips beats two pair, and a flush beats a straight. The poker player’s nymphomaniac exchange student.
Donkey: Like a Fish, but the Donkey does actually know more about poker and the rules, they just tend to ignore them. I guess the real difference though is the Donkey will beat you once and a while with their bad play, while the fish is a more consistent ATM.
Weak Tight: Like a TAG player in terms of hand selection, but avoids flops that don’t hit really hard and can often be bet out of hands. Players moving from full ring and or tournament games to short handed cash games often start as a version of weak tight till they can evolve their game. A blind stealer’s wet dream.
ABC: Somewhat like a TAG player, however they are less aggressive and play by the book. More predictable these players tend to play their hands the same way and rarely mix up their play. ABC players tend to get crushed at higher skill levels.
Maniac: A hyper aggressive version of a LAG player, raising and reraising with anything. They can often push with nothing, counting on a big chip stack to bully the table. Tournament poker play has some times in the game where this type of play will work very well. Win and loose big pots.
Nit: Like an ABC player, but a NIT tends to avoid confrontations and big pots unless they hold the absolute nuts. Like a ABC and a weak player combined. Easy to steal from and check raising often will give you the goods.