Used when someone is punished or treated harshly to serve as a warning to others. Often appears in phrases like 見せしめにする or 見せしめのため.
He was fired as an example to others.
The teacher made the late student stand in the hallway as a warning to the rest.
Compound of 見せ (mise, the continuative form of 見せる 'to show') and しめ (shime, the continuative form of しめる 'to make known, to teach a lesson'). Literally 'showing a lesson'.