Zombie
A zombie is a player with no tells: he has a poker face, shows no emotion and gives no sign of his hand. It is hard to read him.
The simple explanation
A zombie sits still and does the same thing every time. He does not talk, look around or change his behavior, so you cannot learn anything from him. The best way to deal with him is to rely on his betting patterns.
A closer look
Zombies are common at live poker, where players wear sunglasses and hoods to hide their expression. Against a zombie, you should pay attention to bet sizes, timing and patterns instead of physical tells. Remember that stillness is also a kind of tell if it changes. The best players mix some natural behavior with discipline. Online, every player is a kind of zombie, since you do not see them.
A practical example
A player sits very still, with sunglasses and headphones, and nothing he does gives away his hand. The others call him a zombie.
Full explanation
A zombie is a player with no tells: he has a poker face, shows no emotion and gives no sign of his hand. It is hard to read him.
A zombie is a player who gives no tells.
He has a poker face.
Read his betting patterns instead.
Online players are like zombies, because you cannot see them.