In Valorant, the term "CT" stands for "Counter-Terrorist." It is a callout used to indicate the location of an enemy player who is in one of the bomb sites that the defending team needs to protect. The term originates from the game Counter-Strike, where one team plays as terrorists and the other plays as counter-terrorists. So when someone gives the callout "CT" in Valorant, they are notifying their teammates that there is an enemy in one of the bomb sites or possibly rotating from a defensive position.
