substitution, n. replacement, relief, supersession, supplanting, subrogation, surrogation; deputation, delegation, exchange,
substratum, n. base, basis, foundation, footing, groundwork, substructure, substruction, understructure; frame, underlayer, floor, bed.
substructure, n. foundation, groundwork, underbuilding, understructure, substruction; basement, cellar, subcellar; base, bottom, underlayer, floor, bed, rest, frame, Naut. keel,
subterfuge, n. device, contrivance, expedient, Inf. dodge, fetch, blind; manuever, feint, deception, sleight, coup, blow, stroke; artifice, stratagem, trick, deceit, wile, ruse, Trojan horse; fake, sham, hoax, swindle, shuck, fraud; shift, move, evasion, shuffle; prevarication, untruth, lie, fib, falsehood; intrigue, plot, plan, scheme, strategy, machination; conspiracy, complot, cabal.
subterranean, adj. 1. underground, hypogeal, hypo-geous, subterrestrial; below the surface, buried, sunk. 2. hidden, secret, sub rosa, under wraps; concealed, ensconced, shrouded, cloaked, veiled, masked, screened, in the dark; undercover, clandestine, covert, under one's hat, furtive, backdoor, surreptitious; sly, stealthy, sneaky, sneaking, underhand, underhanded,
subtilize, v. 1. elevate, sublimate, exalt, heighten, uplift, magnify, ennoble, raise up.
2. sharpen, intensify, deepen, enhance, whet, pique; quicken, accelerate, inflame, increase, augment.
3. refine, rarefy, attenuate, thin out; volatilize, etherealize.
4. discriminate, split hairs, quibble, cavil, pettifog; evade, equivocate, beat about the bush, reason in a circle, beg the question; varnish, gloss over.
subtle, adj. 1. thin, tenuous, slender, slight, attenu ated; filmy, diaphonous, sheer, gossamer, gossamery, silken, transparent; ethereal, volatile, light, buoyant, floating, unsubstantial, imponderous; rarefied, refined, sublimated.
2. delicate, fine, nice, intricate, elegant, exquisite; not obvious, faint, mysterious.
3. astute, acute, keen, shrewd, sagacious, discerning, penetrating, discriminating, deep, profound.
4. crafty, cunning, wily, foxy, sly, artful, tricky; insidious, strategic, designing, casuistic, Machiavellian, jesuitical; insinuating, shifty, deceptive, crooked, underhand, stealthy.
5. clever, ingenious, expert, skillful, adroit, dexterous, deft, Fr. au fait', quick, apt, Brit. Dial, feat, slick, smart, crackerjack; proficient, masterly, accomplished, versed, experienced, finished, neathanded, fine-fingered, artistic, sophisticated, resourceful.
subtlety, n. 1. thinness, slenderness, slightness, at-tentuation; sheerness, transparency, silkiness; lightness, airiness, etherealness, buoyancy, unsubstantiality.
2. delicacy, fineness, nicety, intricacy, elegance, exquisiteness; rareness, refinement, rarefaction.
3. astuteness, acuteness, keenness, shrewdness, sharpness, acumen; sagaciousness, discernment, discrimination, depth, profundity.
4. craftiness, cunning, slyness, guile, artfulness; insidiousness, stratagem, intrigue, casuistry, Machiavellianism, Disparaging, jesuitism, deception, artifice.
5. cleverness, ingenuity, expertness, skillfulness, adroitness, dexterity, deftness; proficiency, mastery, accomplishment, resourcefulness.