Subtility

CIDE DICTIONARY

Subtility, n. [L. subtilitas: cf. F. subtilité. See Subtle.].

 Subtilty.  [1913 Webster]

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.