Adamance is a term used to describe a person's stubbornness or firmness of belief. There are several synonyms that can be used for this word, including persistence, determination, tenacity, obstinacy, and inflexibility. Persistence refers to the ability to continue doing something despite difficulties, while determination implies a strong will to achieve a goal. Tenacity is the ability to hold fast to something without letting go, while obstinacy implies a refusal to change one's mind or behavior. Inflexibility refers to a lack of adaptability and an inability to change one's position. All these words reflect the same quality of adamance in different contexts.