|Here is the USGA definition of addressing the ball:|
Addressing the Ball
A player has "addressed the ball" when he has taken his stance and has also grounded his club, except that in a hazard a player has addressed the ball when he has taken his stance.
Grounding the club is touching the club to the ground. It does not matter if it's a light touch or a firm press into the ground. There can be no shades of gray in the addressing the ball definition. One either has addressed (taken stance, touched ground) or they have not.
If he did not touch the ground and the ball moved no penalty is applicable.