Sub normal is a term used to describe something that is below average or below the standard. Antonyms for sub normal are words that describe something that is above average or exceeds the standard. Synonyms of sub normal can include words like inadequate, insufficient, or below par. Antonyms for sub normal, on the other hand, can include words like exceptional, outstanding, or exemplary. These words portray something that is above and beyond what is considered typical or standard. Other antonyms can be words like excellent, remarkable, superb, or exceptional which suggest a quality or a level of excellence that is above average or exceeds expectations.