hardhead

noun

1. One who is practical or hardheaded.
2. A brown diving duck, Aythya australis, native to Australia.
3. Any of certain saltwater sciaenid (Sciaenidae) fishes.
4. Mylopharodon conocephalus of fresh waters in California.
5. Any of several weeds in or formerly classified in the genus Centaurea, especially Russian knapweed (Acroptilon repens).
6. Residual ore that failed to melt during a smelting process.
7. (obsolete)Clash or collision of heads in contest.

   “Both play at hardhead till they break their brains”

8. (historical)A Scottish billon coin circulated in the reigns of Mary and James VI.