Fair to middling is a phrase that is commonly used to express something or someone as being average or just okay, not particularly good or bad. The antonyms for "fair to middling" would therefore be words that describe something as being either exceptionally good or exceptionally bad. Words that could be used as antonyms for "fair to middling" might include excellent, exceptional, outstanding, superior, wonderful, marvelous on the positive side or dreadful, terrible, appalling, awful, atrocious, lousy or miserable are antonyms that describe it negatively. Therefore, instead of saying something is simply "fair to middling," we could say it's either fantastic or disastrous, depending on the situation.