Forgiveness is how well the ball will be played if you miss the ding. Clubs with low forgiveness will send the ball a long way off line, ones with high forgiveness will generally still get the ball close to where you want it. Precision must not be forgotten though, it's at least as important as forgiveness, if not more.
The meter speed indicator means slowest when it's pointing at 9 o'clock and fastest when it's heading towards 3 o'clock.