1.  falseness(n = noun.state) falsity - the state of being false or untrue; "argument could not determine its truth or falsity"
is a kind of irreality, unreality
has particulars: spuriousness
Derived forms adjective false₂, adjective false₅, adjective false₁

2.  falseness(n = noun.attribute) faithlessness, fickleness, inconstancy - unfaithfulness by virtue of being unreliable or treacherous;
is a kind of infidelity, unfaithfulness
Derived form adjective false₄

3.  falseness(n = noun.attribute) hollowness, insincerity - the quality of not being open or truthful; deceitful or hypocritical;
is a kind of untruthfulness
has particulars: hypocrisy
Derived forms adjective false₁₀, adjective false₉

   The state of being false; contrariety to the fact; inaccuracy; want of integrity or uprightness; double dealing; unfaithfulness; treachery; perfidy; as, the falseness of a report, a drawing, or a singer's notes; the falseness of a man, or of his word. [1913 Webster]

N  undueness, malum prohibitum, impropriety, illegality, falseness, emptiness of title, invalidity of title, illegitimacy, loss of right, disfranchisement, forfeiture, usurpation, tort, violation, breach, encroachment, presumption, assumption, seizure, stretch, exaction, imposition, lion's share, usurper, pretender, undue, unlawful, unconstitutional, illicit, unauthorized, unwarranted, disallowed, unallowed, unsanctioned, unjustified, unentitled, disentitled, unqualified, disqualified, unprivileged, unchartered, illegitimate, bastard, spurious, supposititious, false, usurped, tortious, undeserved, unmerited, unearned, unfulfilled, forfeited, disfranchised, improper, unmeet, unfit, unbefitting, unseemly, unbecoming, misbecoming, seemless, contra bonos mores, not the thing, out of the question, not to be thought of, preposterous, pretentious, would-be, filius nullius.

N  falsehood, falseness, falsity, falsification, deception, untruth, guile, lying, untruth, guile, lying, misrepresentation, mendacity, perjury, false swearing, forgery, invention, fabrication, subreption, covin, perversion of truth, suppression of truth, suppressio veri, perversion, distortion, false coloring, exaggeration, prevarication, equivocation, shuffling, fencing, evasion, fraud, suggestio falsi, mystification, simulation, dissimulation, dissembling, deceit, blague, sham, pretense, pretending, malingering, lip homage, lip service, mouth honor, hollowness, mere show, mere outside, duplicity, double dealing, insincerity, hypocrisy, cant, humbug, jesuitism, jesuitry, pharisaism, Machiavelism, organized hypocrisy, crocodile tears, mealy-mouthedness, quackery, charlatanism, charlatanry, gammon, bun-kum, bumcombe, flam, bam, flimflam, cajolery, flattery, Judas kiss, perfidy, il volto sciolto i pensieri stretti, unfairness, artfulness, misstatement, false, deceitful, mendacious, unveracious, fraudulent, dishonest, faithless, truthless, trothless, unfair, uncandid, hollow-hearted, evasive, uningenuous, disingenuous, hollow, sincere, Parthis mendacior, forsworn, artificial, contrived, canting, hypocritical, jesuitical, pharisaical, tartuffish, Machiavelian, double, double tongued, double faced, double handed, double minded, double hearted, double dealing, Janus faced, smooth-faced, smooth spoken, smooth tongued, plausible, mealy-mouthed, affected, collusive, collusory, artful, perfidious, spurious, untrue, falsified, covinous, falsely, a la tartufe, with a double tongue, silly, blandae mendacia lingua, falsus in uno falsus in omnibus, I give him joy that's awkward at a lie, la mentira tiene las piernas cortas, O what a goodly outside falsehood hath.

N  deception, falseness, untruth, imposition, imposture, fraud, deceit, guile, fraudulence, fraudulency, covin, knavery, misrepresentation, bluff, straw-bail, straw bid, spoof, delusion, gullery, juggling, jugglery, slight of hand, legerdemain, prestigiation, prestidigitation, magic, conjuring, conjuration, hocus-pocus, escamoterie, jockeyship, trickery, coggery, chicanery, supercherie, cozenage, circumvention, ingannation, collusion, treachery, practical joke, trick, cheat, wile, blind, feint, plant, bubble, fetch, catch, chicane, juggle, reach, hocus, bite, card sharping, stacked deck, loaded dice, quick shuffle, double dealing, dealing seconds, dealing from the bottom of the deck, artful dodge, swindle, tricks upon travelers, stratagem, confidence trick, fake, hoax, theft, ballot-box stuffing, barney, brace game, bunko game, drop game, gum game, panel game, shell game, thimblerig, skin game, snare, trap, pitfall, decoy, gin, springe, springle, noose, hoot, bait, decoy-duck, tub to the whale, baited trap, guet-a-pens, cobweb, net, meshes, toils, mouse trap, birdlime, dionaea, Venus's flytrap, ambush, trapdoor, sliding panel, false bottom, spring-net, spring net, spring gun, mask, masked battery, mine, flytrap, green goods, panel house, Cornish hug, wolf in sheep's clothing, disguise, disguisement, false colors, masquerade, mummery, borrowed plumes, pattes de velours, mockery, copy, counterfeit, sham, make- believe, forgery, fraud, lie, a delusion a mockery and a snare, hollow mockery, whited sepulcher, painted sepulcher, tinsel, paste, junk jewelry, costume jewelry, false jewelry, synthetic jewels, scagliola, ormolu, German silver, albata, paktong, white metal, Britannia metal, paint, veneer, jerry building, man of straw, illusion, ignis fatuus, mirage, deceived, deceiving, cunning, prestigious, prestigiatory, deceptive, deceptious, deceitful, covinous, delusive, delusory, illusive, illusory, elusive, insidious, ad captandum vulgus, untrue, mock, sham, make-believe, counterfeit, snide, pseudo, spurious, supposititious, so-called, pretended, feigned, trumped up, bogus, scamped, fraudulent, tricky, factitious bastard, surreptitious, illegitimate, contraband, adulterated, sophisticated, unsound, rotten at the core, colorable, disguised, meretricious, tinsel, pinchbeck, plated, catchpenny, Brummagem, artificial, synthetic, ersatz, simulated, under false colors, under the garb of, under cover of, over the left, keep the word of promise to the ear and break it t, fronti nulla fides, ah that deceit should steal such gentle shapes, a quicksand of deceit, decipimur specie recti, falsi crimen, fraus est celare fraudem, lupus in fabula, so smooth, he daubed his vice with show of virtue.