pigheadedadj.

pigheaded (adj.)also pig-headed; 1756, "having a head resembling a pig;" 1788 as "obstinate;" see pig (n.) + head (n.). Usually, but not always, figurative. A pig-headed man must be one, who, like a driven pig, always will do exactly the opposite to what other people--in the case of the pig his luckless driver--wish him to do, that is to say he is an obstinate man. ["The Sedberghian," June 1882]