Bill Fleckenstein to trader: Stop being a jerk

After years of calling for a correction, noted short-seller Bill Fleckenstein now says this market is un-shortable — and that got under the skin of "Fast Money" trader Tim Seymour.

In a heated debate on Thursday, Seymour slammed the Fleckenstein Capital founder for allegedly flip-flopping on his call that the markets are on the verge of a massive meltdown.

"You've been on this show a number of times where you've been licking your chops saying it's about to happen, and it's two or three years going on doing this, and a lot of it sounds pretty pathetic," said Seymour. "You're almost throwing in the towel."

Fleckenstein has long been in the camp that excessive monetary policies from central banks has created a bubble so large that any prick could create a swift and sudden downturn for equities. In January of 2016 Fleckenstein predicted the market would continue to fall "hard and fast." Soon after his call, the S&P 500 fell to a low of around 1,810 in February but has since recovered.

Despite the criticism, Fleckenstein maintained that he is still weary of the market at current levels. "I'm not throwing in the towel," he proclaimed. He noted that since the end of quantitative easing in October 2014, stocks have merely "limped higher," failing to make meaningful gains until a breakout in early summer. "I'm doing exactly what I've been doing … and that's being long gold and the miners."

Still, Seymour contended that the short-seller be held responsible for his past calls, saying, "It sounds like you missed a lot … a lot of this sounds kind of pathetic." To which Fleckenstein responded for Seymour to "stop being such a jerk."

The S&P 500 closed Thursday within 1 percent of its all-time high, while the Nasdaq finished the session at a record.