Doesn't matter if a heckler hurled the n-word, pro athletes like Leonard Fournette need to WALK AWAY from trash talkers ... 'cause if they actually fight, a pro could literally KILL a loudmouthed normie.
That's the advice coming from Charles Barkley -- who's dealt with plenty of hecklers during and after his NBA career.
Chuck knows trash talk is all fun and games until things turn physical -- and that's when things can get way too real.
"If you hit a fan and hurt them, you might KILL them," Barkley explained .