Wiktionary
fair to middling
a. (context idiomatic usually hyphenated when placed before noun English) Only tolerably good; somewhat favorable. alt. (context idiomatic usually hyphenated when placed before noun English) Only tolerably good; somewhat favorable.
WordNet
Usage examples of "fair to middling".
But Belle Starr's father had been a judge back in Missouri, and Belle had a little education, she played the piano fair to middling, and she wanted above all to be a lady.