Merriam-Webster Collegiate Dictionary - obstinate

 adjective  Etymology: Middle English, from Anglo-French obstinat, Latin obstinatus, past participle of obstinare to be resolved, from ob- in the way + -stinare (akin to stare to stand)  Date: 14th century  1. perversely adhering to an opinion, purpose, or course in spite of reason, arguments, or persuasion ~ resistance to change  2. not easily subdued, remedied, or removed ~ fever  • ~ly adverb  • ~ness noun Synonyms:  ~, dogged, stubborn, pertinacious, mulish mean fixed and unyielding in course or purpose. ~ implies usually an unreasonable persistence an ~ proponent of conspiracy theories. dogged suggests an admirable often tenacious and unwavering persistence pursued the story with dogged perseverance. stubborn implies sturdiness in resisting change which may or may not be admirable a person too stubborn to admit error. pertinacious suggests an annoying or irksome persistence a pertinacious salesclerk refusing to take no for an answer. mulish implies a thoroughly unreasonable obstinacy a mulish determination to have his own way.