Pervicacious is a unique term, but if you're searching for alternatives, here are a few: Stubborn, obstinate, inflexible, rigid, unyielding, willful, dogged, tenacious, immovable and resolute. Pervicacious generally refers to someone who stubbornly holds onto a belief, idea, or course of action in the face of reasonable argument or evidence. Synonyms for it attempt to capture roughly the same sentiment, making use of words that connote tenacity, fortitude, or intransigence. It is always good to have a strong vocabulary, explore and use synonyms for words as it increases your proficiency in communication.