O.B. (Oscar Bravo, Set it Free): Out-of-bounds.
Off-Center Hit: Less than a solid strike.
Offset: Club with the head set farther behind the shaft than normal.
One-Putt: To take only a single putt on a green.
One Up: Being one hole ahead in the match score.
Open Face: Clubface aligned to the right of the target at address, or to the right of its path at impact. Can lead to a shot going to the right of the target.
Open Stance: Player sets up with the left foot pulled back, away from the ball.
Open Up the Hole: When your tee shot leaves the best possible angle for the next shot to the green.
Out-of-Bounds: Area outside the boundaries of the course, usually marked with white posts. When a ball finishes “O.B.,” the player must return to the original spot and play another ball under penalty of one stroke. He or she thus loses stroke and distance.
Outside: Area on the far side of the ball.
Outside In: Swing path followed by the clubhead into the ball from outside the ball-target line. (See inside out.)
Over the Green: Ball hit too far.
Overclub: To use a club that will hit the ball too far.
Overlapping: A type of grip where the little finger of the right hand lies over the index finger of the left hand.