subtilty
/ˈsʌtlti/ /ˈsʌbt(ɪ)lti/Now rare (chiefly superseded by subtlety)
noun
1A refinement of thought or argument; a fine point; = subtlety. Usually in plural.
2Refinement in argument or speculation; (excessive) use of fine distinctions.
3 Cookery. = subtlety. historical after 16th cent.
Origin
Late Middle English (in an earlier sense). Partly an alteration of subtlety after subtile, and partly a variant of subtility with reduction of the final syllable.