Meaning

adjective not common or ordinarily encountered; unusually great in amount or remarkable in character or kind

adjective marked by an uncommon quality; especially superlative or extreme of its kind; -J.R.Lowell

originEtymology tree Proto-Indo-European *né Proto-Indo-European *n̥- Proto-Germanic *un- Proto-West Germanic *un- Old English un- Middle English un- English un- English common English uncommon From un- + common.

Etymology from Wiktionary, CC BY-SA 3.0