Something real. Unscripted. When someone goes off-script on the mic, that's a shoot promo. When two wrestlers legitimately don't like each other and start throwing real punches, that's a shoot fight. The line between work and shoot has gotten so blurred in the modern era that half the fun is trying to figure out which is which.
"That wasn't in the script. He went into business for himself and shot on his opponent live on air."