The adj uncommon has 2 senses (first 1 from tagged texts)
1. (4) uncommon -- (not common or ordinarily encountered; unusually great in amount or remarkable in character or kind; "uncommon birds"; "frost and floods are uncommon during these months"; "doing an uncommon amount of business"; "an uncommon liking for money"; "he owed his greatest debt to his mother's uncommon character and ability")
2. rare, uncommon -- (marked by an uncommon quality; especially superlative or extreme of its kind; "what is so rare as a day in June"-J.R.Lowell; "a rare skill"; "an uncommon sense of humor"; "she was kind to an uncommon degree")