Word parts un- + common Pronunciation IPA (key): /ʌnˈkɒmən/ Audio (UK)(file) Adjective Positive uncommon Comparative uncommoner Superlative uncommonest If something is uncommon it does not occur or appear very often. Synonym: rare Antonyms: common and often It is uncommon for a divorced couple to forgive one another. It is uncommon to see an alligator this far north.Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads