Kyle Kuzma Fined $15K For Flipping Middle Finger At Fan

Kyle Kuzma's middle finger just cost him -- the NBA just hit the Wizards forward with a $15,000 punishment ... after he flipped the bird at a fan earlier this week.

The incident took place when Kuzma -- a native of Michigan -- was in town playing against his hometown Detroit Pistons.

The Wizards were winning 94-88 in the fourth quarter when Kuz nailed a corner three ... then turned around and gave a fan the middle finger gesture.

Unclear what, or even if, the fan said something ... but you can tell Kuzma did it deliberately.

The game went to overtime -- Kuzma finished with a team-high 28 points and his team secured the W, 119-116 ... but let's be honest, the bird was the highlight of the night.

Of course, this isn't the first time Kuz has gone at fans this season -- he nailed a dagger three against the Cleveland Cavaliers, and blamed hecklers for motivating him to knock down the game-winning shot.

Kuzma is typically a good sport ... when social media roasted him for wearing that oversized pink sweater, Kyle seemed to go along with the jokes.