1. (n.) The quality or state of being rare; rareness; thinness; as, the rarity (contrasted with the density) of gases.

2. (n.) That which is rare; an uncommon thing; a thing valued for its scarcity.

abnormality airiness airy texture amazement anomaly astonishing thing astonishment attenuation chinchiness chintziness conversation piece curio curiosity dearth delicacy diaphanousness dilutedness dilution ethereality exception exceptionality exiguity exility extraordinariness fabulousness fewness find fineness flimsiness frailty gauziness gazingstock gossameriness gracility impossibility improbability inconceivability incredibility increditability infrequence infrequency insubstantiality laciness lightness marvel marvelment marvelousness meagerness miracle miserliness mistiness museum piece mythicalness nonesuch occasionalness oddity paperiness paucity phenomenon poverty prodigiosity prodigiousness prodigy quite a thing rareness remarkableness restrictedness scant sufficiency scantiness scarceness scarcity scrimpiness seldomness sensation sight skimpiness slenderness slightness slimness slowness smallness something else sparseness sparsity spectacle stinginess strange thing stringency stunner stupendousness subtility tenuity thinness tightness treasure uncommonness unfrequentness uniqueness unordinariness unusualness unwontedness vagueness wateriness weakness wispiness wonder wonderful thing wonderment