Assentor is a relatively uncommon word that refers to someone who agrees with or supports another person's viewpoint or perspective. There are several synonyms for the word assentor that can be used to convey similar meanings. Some examples include supporter, ally, advocate, adherent, champion, defender, endorser, backer, and proponent. Each of these words has slightly different connotations and may be used in different contexts to describe someone who agrees with or supports another person or group. Regardless of the word used, the underlying meaning remains the same - that of a person who is in agreement with someone else or who supports their views or opinions.