rare

adj

1.
not widely known; especially valued for its uncommonness
2.
recurring only at long intervals
Derived from:
rareness
3.
not widely distributed
Derived from:
rareness rarity
4.
having low density
rarefied rarified
Derived from:
rarity
5.
marked by an uncommon quality; especially superlative or extreme of its kind
uncommon
Derived from:
rarity
6.
(of meat) cooked a short time; still red inside