adj. (common).1. Oafish; stupid.
1600. NASHE, Summers Last Will (GROSART), vi., 169. A number of rude Vulcans, vnweldy speakers, HAMMER-HEADED clowns.
2. (colloquial).Hammer-shaped: i.e., long and narrow in the head.
1865. DICKENS, Our Mutual Friend, i., 9. Mr. Boffins equipage consisted of a long HAMMER-HEADED old horse, formerly used in the business . And a driver being added, in the person of a long HAMMER-HEADED young man.