curtail dog

Wiktionary

1. n. obsolete A dog with a docked tail; formerly, the dog of a person not qualified to course, which, by the forest laws, must have its tail cut short, partly as a mark, and partly from a notion that the tail is necessary to a dog in running.
2. n. obsolete, by extension A dog not fit for sporting.

GNU Webster's 1913

1. A dog with a docked tail; formerly, the dog of a person not qualified to course, which, by the forest laws, must have its tail cut short, partly as a mark, and partly from a notion that the tail is necessary to a dog in running; hence, a dog not fit for sporting.