For a professonal trader I define it as making money every month (unless you're very long term, then it's not so possible).
LOOK at the action in the markets, almost EVERY day there are great moves, doesn't matter which market. So to be a pro, you have to be able to harvest some of that whilst keeping losses under control. If you're not making money every month then you need to work on your game-plan.
Interestingly I'm just reading Soros's Alchemy of Finance where he details his trades and thinking from the mid-1980s. Fascinating how he gets suckered by the markets here and there, buying the high, selling the lows, fucking up his profit taking (like most of us!) and so on. He scores massive FX gains on the 1985 Plaza deal but admits that all those profits pay off all his FX losses for the past 4 years! So here's one of the best money managers and for several years all he gets is losses in FX. Of course, those losses are more than made up via profits from the rest of his portfolio.
The advantage that most of us have against a massive portfolio is we can be in/out all day long if need be. That's a REAL EDGE so use it...