Mawson, C.O.S., ed. (1870–1938). Roget’s International Thesaurus. 1922.

Class VI. Words Relating to the Sentient and Moral Powers
Section IV. Moral Affections
3. Moral Conditions

940. Improbity.

   NOUN:IMPROBITY, dishonesty, dishonor; deviation from rectitude; disgrace (disrepute) [See Disrepute]; fraud (deception) [See Deception]; lying [See Falsehood]; mouth honor (flattery) [See Flattery]; bad faith, mala fides [L.], Punic faith, Punica fides [L.]; infidelity; faithlessness &c. adj.; Judas kiss, betrayal; perfidy; perfidiousness &c. adj.; treachery, double dealing; unfairness &c. adj.
  breach of -promise, – trust, – faith; prodition [obs.], disloyalty, divided allegiance, hyphenated allegiance [cant], treason, high treason; apostacy (tergiversation) [See Tergiversation]; nonobservance [See Nonobservance].
  shabbiness &c. adj.; villainy; baseness &c. adj.; abjection, debasement, degradation, turpitude, moral turpitude, laxity, trimming, shuffling.
  KNAVERY, roguery, rascality, foul-play; jobbing, jobbery, graft [colloq.], venality, nepotism; corruption, job, shuffle, fishy transaction; barratry [law], sharp practice, heads I win tails you lose.
   VERB:BE DISHONEST &c. adj.; play false; break one’s -word, – faith, – promise; jilt, betray, forswear; shuffle (lie) [See Falsehood]; play with marked cards, cheat at cards, live by one’s wits, sail near the wind.
  disgrace -, dishonor -, lower -, demean [colloq.] -, degrade- oneself; derogate, stoop, grovel, sneak, lose caste; sell oneself, squeal [slang], go back on [colloq.], go over to the enemy; seal one’s infamy.
   ADJECTIVE:DISHONEST, dishonorable; unconscientious, unscrupulous; fraudulent [See Deception]; knavish; disgraceful (disreputable) [See Penalty]; wicked [See Vice].
  false-hearted, disingenuous; unfair, one-sided; double, double-hearted, double-tongued, double-faced; time-serving, crooked, tortuous, insidious, Machiavellian, dark, slippery; fishy [colloq.], questionable.
  INFAMOUS, arrant, foul, base, vile, low, ignominious, blackguard, perfidious, treacherous, perjured; hyphenated [cant].
  contemptible, abject, mean, shabby, little, paltry, dirty, scurvy, scabby, sneaking, groveling, scrubby, rascally, barratrous [law], pettifogging; corrupt, venal; debased, mongrel; beneath one.
  low-minded, low-thoughted, base-minded.
  DEROGATORY, degrading, undignified, indign [obs.], unbecoming, unbeseeming, unbefitting, infra dignitatem [L.], ungentlemanly, ungentlemanlike; unknightly, unchivaIric, unmanly, unhandsome; recreant, inglorious.
  FAITHLESS, of bad faith, false, unfaithful, disloyal; untrustworthy; trustless, trothless [archaic], lost to shame, dead to honor.
   ADVERB:DISHONESTLY &c. adj.; malâ fide [L.]; like a thief in the night, by crooked paths, by foul means.
   INTERJECTION:O tempora! O mores! [Cicero].    QUOTATIONS:
  1. Corruptissimâ republicâ plurimæ leges.—Tacitus
  2. And seem a saint, when most I play the devil.—Richard III
  3. Crooked counsels and dark politics.—Pope
  4. Honor is without profit—in most countries.—Cynic’s Calendar