The phrase "most second to none" implies the highest level of excellence, with no competition or equal. However, there are multiple antonyms that can be used instead of this phrase to represent the opposite or lower level of excellence. These antonyms include "inferior," "mediocre," "middling," "ordinary," "average," "common," "subpar," "substandard," and "third-rate." These words represent a level of excellence that is lower than expected and does not match the highest standards. Therefore, it is essential to be precise with the words used to convey the intended meaning of excellence.