heeler

noun

1. A gamecock that strikes well with its heels or spurs.
2. A quick runner.

   “That a crowd of Sydney stealers, Jockeys, pugilists and spielers Brought some horses, real heelers, Came and put us through.”

3. A dog that readily comes to heel.

   “If your dog is a good heeler, you'll find some competition in the obedience ring.”

4. (Australia)A dog used for cattle droving.

   “[A] blue roan, a kind of dog that Jennifer had never seen before. She asked Tim what it was, and he said it was a "heeler", but when she pressed him to say if that was a breed or not, he could not tell her. It was a heeler because it went for the heels of the cattle and not their heads, apparently.”

5. (US, dated, slang)A dependent and subservient hanger-on of a political patron.

   “The army of hungry heelers who do their bidding.”

6. The rodeo performer who ropes the steer by its hind feet after the header has turned it.
7. (US)A student journalist at Yale University.