In slang, “wag” can have a few meanings depending on context. Most commonly online, it refers to a “Wives and Girlfriends” (often of athletes), used in sports media and gossip discussions. For example, “The WAGs were spotted at the match” means the players’ partners were present. In other contexts, especially informal British slang, “wag” can also mean someone playful or mischievous, but the “wives and girlfriends” meaning is the most common online use.