ban
MatchmakingDefinition
A ban (in champion select) is the act of removing a champion or hero from the match. Bans prevent the opposing team from picking specific threats and protect against one-tricks. League of Legends has 10 bans per game (5 per team); Valorant Competitive does not have agent bans. Ban is also used for account-level penalties ("got banned for cheating") — a different meaning.
Example
"First-ban Yasuo — they have a one-trick." The team removed an opposing player's signature pick.