Uncommon, a.
Not common; unusual; infrequent; rare; hence, remarkable; strange; as, an uncommon season; an uncommon degree of cold or heat; uncommon courage.
Syn. -- Rare; scarce; infrequent; unwonted. -- Un*com"mon*ly, adv. -- Un*com"mon*ness, n.
Shades of meaning
Fernald has no entry of its own for uncommon; he lists it under queer, rare.
He lists it without comment; the entries above explain its neighbors.