Most amnesic is a phrase used to describe something that causes forgetfulness or memory loss. The antonyms, or opposites, of most amnesic would be words that promote memory and increase cognition. Some antonyms for most amnesic include memorable, unforgettable, retentive, sharp-witted, and cognizant. These words all suggest that something or someone is able to remember things clearly and retain information effectively. Therefore, if you want to improve your memory, you can use antonyms of most amnesic in order to help you remember things better and avoid forgetfulness.