To incapacitate; especially by inducing disorientation or unconsciousness.

“Bill tried to stun the snake by striking it on the head.”

To shock or surprise.

“He stood there stunned, looking at the beautiful, breath-taking sunrise.”

To hit the cue ball so that it slides without topspin or backspin (and with or without sidespin) and continues at a natural angle after contact with the object ball

Unable to act or respond; dazed; shocked.