rare
adj.
not widely known; especially valued for its uncommonness
a rare word|rare books
adj.
recurring only at long intervals
a rare appearance|total eclipses are rare events
adj.
not widely distributed
rare herbs|rare patches of green in the desert
adj.
having low density
rare gasses|lightheaded from the rarefied mountain air
Synonym: rarefied, rarified
adj.
marked by an uncommon quality; especially superlative or extreme of its kind
what is so rare as a day in June|a rare skill|an uncommon sense of humor|she was kind to an uncommon degree
Synonym: uncommon
adj.
(of meat) cooked a short time; still red inside
rare roast beef