The word "most agnostic" implies a level of uncertainty or skepticism when it comes to the existence or nature of a higher power. Some antonyms for this phrase could include "devout," "religious," or "faithful," which all describe individuals who firmly believe in the existence of a higher power and follow a specific set of religious beliefs. Other antonyms could include terms such as "dogmatic," "orthodox," or "zealous," which describe individuals who hold their beliefs with strong conviction and may even be intolerant of those who hold differing views. Ultimately, the antonym for "most agnostic" depends on the specific beliefs and attitudes being contrasted, but it often involves faith and certainty in some form.