Impervious to persuasion means that a person cannot be convinced to change their point of view or opinion. There are many different synonyms for this term, including obstinate, unyielding, stubborn, inflexible, unalterable, intransigent, immovable, and resolute. These words all describe a person who is firm in their beliefs and steadfastly refuses to be swayed by any argument or evidence. Other similar terms include dogmatic, adamant, unshakeable, and indomitable. While it can be frustrating to try to convince someone who is impervious to persuasion, it is important to remember that everyone has their own beliefs and opinions, and it is not always possible or necessary to change them.