ROGET THESAURUS
Subtility
Rarity
N
rarity, tenuity, absence of solidity, subtility, subtilty, subtlety, sponginess, compressibility, rarefaction, expansion, dilatation, inflation, subtilization, vaporization, evaporation, diffusion, gassification, ether, rare, subtile, thin, fine, tenuous, compressible, flimsy, slight, light, cavernous, spongy, rarefied, unsubstantial, uncompact, incompressed, rarefiable.