A run out or stumping can look obvious until you ask whose ground matters, whether the wicket was fairly broken, whether the batter had anything grounded behind the crease, and whether the ball was still live.
A batter can be run out when they are out of their ground and the wicket is fairly broken while the ball is in play. A direct hit, relay throw, or deflection can all matter if the wicket is put down legally.
A stumping is usually a wicketkeeper dismissal against a striker who has left their ground while receiving a legal delivery and is not attempting a run. If the batter is attempting a run, the dismissal is usually treated as a run out instead.
A bat or part of the batter's body must be grounded behind the crease. Being over the line in the air is not enough if nothing is grounded when the wicket is broken.
A wicket is put down when at least one bail is completely removed from the top of the stumps, or a stump is struck out of the ground, by the ball or by a fielder's hand or arm while that hand or arm is holding the ball. A direct throw can remove the bail without a fielder touching it. If both bails are already off, the fielding side must remove a stump from the ground or pull a stump up with the ball held in the same hand. Merely brushing an already bare wicket, or breaking it with an empty hand, does not complete the dismissal.
Stumped is available when the wicketkeeper alone puts down the striker's wicket after a delivery that is not a no-ball, while the striker is out of their ground and is not attempting a run. The striker may have advanced to play or avoid the ball; missing it does not itself decide the appeal. If the striker is attempting a run, or if another fielder makes the decisive intervention, the relevant dismissal is normally run out. A wide can produce a stumping, but a no-ball cannot. A no-ball still permits many run outs, subject to a special protection for a striker who is out of the ground without attempting a run when no fielder other than the wicketkeeper has intervened.
A batter who has grounded the bat or body beyond the crease while running or diving is not treated as short merely because that same contact later lifts accidentally while forward momentum continues. This protection prevents a naturally bouncing bat from undoing ground already made. It does not help someone who never grounded behind the crease, who turns back toward the other end, or who leaves the ground for a new attempt. Replays must establish both the first grounding and what the batter did afterward.