Definition of hardhead
- hardhead Noun A practical person; someone hardheaded.
- hardhead Noun A brown diving duck, "Aythya australis", native to Australia.
- hardhead Noun Any of various freshwater cyprinid fishes of the genus "Mylopharodon", or of saltwater sciaenid (Sciaenidae) fishes.
- hardhead Noun Any of several weeds in or formerly classified in the genus "Centaurea", particularly russian knapweed ("Acroptilon repens").
- hardhead Noun Residual ore that failed to melt during a smelting process.