A cub, child, pup, kit, or any other kind of offspring that is the product of incest.

Examples:

Father x Daughter = inbred child.

Father x son (if the son is capable of becoming pregnant) = inbred child.

Mother x son = inbred child.

Brother x sister = inbred child.

Grandparent x grandchild = inbred child.

Uncle/Aunt x nephew/niece = inbred child.

The list goes on and on, but I think you get the idea. :3