Origin and history of subtlety

c. 1300 (mid-13c. as a surname), sotil, "penetrating; ingenious; refined" (of the mind); "sophisticated, intricate, abstruse" (of arguments), from Old French sotil, soutil, subtil "adept, adroit; cunning, wise; detailed; well-crafted" (12c., Modern French subtil), from Latin subtilis "fine, thin, delicate, finely woven;" figuratively "precise, exact, accurate," in taste or judgment, "fine, keen," of style, "plain, simple, direct."

This is from sub "under" (see sub-) + -tilis, from tela "web, net, warp of a fabric," a derivative of texere "to weave, construct" (see text (n.)). According to Watkins, the notion is of the "thread passing under the warp" as the finest thread. The English word has been partially re-Latinized in spelling, and altered by confusion with subtile.

It is attested from early 14c. in English in reference to things, "of thin consistency;" in reference to craftsmen, "artful, skilled, clever." The depreciative sense of "insidious, treacherously cunning; deceitful" is attested from mid-14c.

The material senses of "not dense or viscous, light; pure; delicate, thin, slender; fine, consisting of small particles" are from late 14c. Sotil wares were goods sold in powdered form or finely ground.

c. 1300, sotil; the modern form is attested from late 14c., "clever, dexterous, crafty;" of fluids, "not dense, thin, rarefied;" of fabrics, "of fine or delicate texture;" from Old French subtil (14c.), a learned Latinized reformation of earlier sotil (12c.), source of subtle (q.v.).

It is a doublet or variant of subtle, originally used in all the same senses. Some lines of Chaucer that have the word alternate between the two spellings in different transcriptions. And compare subtilty, a late 14c. variant of subtlety altered by influence of this word.

Subtile still is used in some Bible translations in Genesis iii.1, and it survived past 17c. in some material senses ("fine, delicately constituted, thin") as a parallel formation to subtle. Related: Subtilly; subtilely.

late 14c., "acuteness, skill, cunning," an alteration of subtlety (q.v.) on model of subtile, or else from Old French subtilite, from Latin subtilitas "fineness, simplicity." It had formerly all the senses of subtlety, but now is used in the material senses associated with subtile.