PvP
PvP stands for "Player versus Player" in Rust.
A PvP server is a server for the game Rust that is focused on players engaging in direct combat against one another. Players on a PvP server typically focus on gathering resources, building structures, and competing against one another for survival. These servers usually have no rules or restrictions on player versus player actions, such as raid, friendly fire on, etc.
In a PvP server, players can raid other player's bases, kill other players and take their loot, and form alliances or clans with other players to gain an advantage over others. It's up to the players to decide their own playstyle, but it's generally considered that PvP servers are more aggressive and fast-paced than PvE servers, and require more strategy, skill and teamwork to survive.