When something stimies you, it stops you from doing what you want to do, especially in golf.
If something stimies you, it is usually frustrating because it gets in your way.
Examples:
The tree stimies the golf ball.
I tried to hit the ball, but the tree stimies me.
The tree stimies me from hitting the ball.
The sneaky tree always stimies my golf game.
The huge tree always stimies me from winning.
The tree is like a big wall that stimies me every time.