Restrained

     The creature can’t move, unless it teleports. It can’t even be pulled, pushed, or slid.
     The creature takes a -2 penalty to attack rolls.
     The creature grants combat advantage.

This condition is similar to the immobilized condition (see above), but it puts more restrictions on the creature’s ability to attack or defend itself. This condition usually results from being held in place by something: vines, tentacles, manacles attached to a wall, strands of webbing, or a monster’s gaping jaws. Whatever is holding the creature in place interferes with its ability to move around freely.

Published in Player's Handbook, page(s) 277, Player's Handbook 3, page(s) 222, Rules Compendium, page(s) 233, Monster Vault: Threats to the Nentir Vale, page(s) 125.