A butt chin is a chin with a line down the middle, resembling a butt. A chin butt, therefore, is a butt without a crack.

a dimple on the chin, just as envied as cute dimples on the cheeks

a term often used to connote jealousy of the beauty of the person who has the dimple

adj.
a chin that has a small/large dent in the center.

a dimple on the chin, just as envied as cute dimples on the cheeks a term often used to connote jealousy of the beauty of the person who has the dimple

A beauty mark

A butt chin is something to be admired. Not many have it, and the few that do should be cherished. If you have a mild butt chin you can enhance its prominence by getting a few select friends who will pinch it a lot and help it achieve its best form.

A person with an indent in the middle of their chin, resembling the characteristics of a butt.

Andy Dick.