Every player, most of the objects, and also some monsters are "pushable" in-game. This feature was put in game mainly to avoid trapping, but also is used to some other activities, such as wrestling in the Venore's Game Hall.
To push something, simply left click the tile the it is on, drag the pointer to the tile of where you want it, and release the mouse click. Players can also "throw" some things more than one tile away, depending on the object's size. Players cannot be pushed out of protection zones, and monsters cannot be pushed into them.
Since the update of 7.8, after killing a monster with volume, no one is able to push the body for 10 seconds. Also, only the player who does the most damage (and the people in that player's party) can loot the body in that time.
Be warned to use the pushing function wisely, because it can cause more problems than you started with if not used correctly. For example, pushing people around can cause them to dislike you. Furthermore, it is possible to push your equipment or loot bag into a dustbin!