Hot-miking (derived from "hot mic") is a term used in online gaming, describing the occurance of an online user unintentionally using the in-game voice chat, allowing unintended listeners (possibly of the enemy team) to hear private or tactical conversations.
A hot mic may also be called: microphone gaffe, open microphone or stuck microphone
global chat, Team 1 Hot micing player: "Hey, we're gonna flank them from the North!".
Opponent team chat Enemy Player: Guys there's somebody hot-miking on the enemy team. I've heard they're gonna flank us from the north!"