1. (n.) The quality of being improper; unfitness; unsuitableness; inappropriateness; as, impropriety of behavior\ or manners.

2. (n.) That which is improper; an unsuitable or improper act, or an inaccurate use of language.

Babbittry Gothicism aberrance aberrancy abnormality anomaly atrocity bad taste badness barbarism barbarousness blunder bombasticness bourgeois taste breach cacology cacophony camp campiness clumsiness coarseness colloquialism corruption crime crime against humanity criminality crudeness cumbrousness deadly sin delinquency dereliction deviance deviancy discourtesy disentitlement disorder disorderliness disorderly conduct disruption disruptiveness dysphemism empty claim empty title enormity erroneousness error evil excess failure false claim falseness falsity fault faux pas felony frowned-upon behavior gaffe gaucherie genocide gracelessness grossness guilty act harshness heaviness heavy sin high camp hooliganism horseplay ill-balanced sentences illegality immodesty immorality imprecision improperness impurity inaccuracy inaccurateness inadmissibility inapplicability inappositeness inappropriateness inaptitude inaptness inauspiciousness incompatibility inconcinnity incongruity incongruousness inconvenience incorrectness indecency indecorousness indecorum indelicacy indiscreetness indiscretion inelegance inelegancy inequitableness inequity inexactitude inexactness inexpedience inexpiable sin infelicity infraction iniquitousness iniquity injury injustice inopportuneness inopportunity intempestivity interruption intrusion invalid claim irregularity irrelevance irrelevancy kitsch lack of claim lack of finish lack of polish lapse lasciviousness lateness leadenness lewdness localism low camp maladjustment malefaction malfeasance malum mesalliance minor wrong misalliance misbehavior misconduct misdeed misdemeanor misdoing misfeasance misjoinder misjoining mismatch mistake mortal sin naughtiness no claim nonfeasance nonsanctioned behavior offense omission outrage peccadillo peccancy philistinism pompousness ponderousness poor diction poor taste pop pop culture prematurity roughhouse roughness rowdiness rowdyism rudeness ruffianism sesquipedalianism sesquipedality sin sin of commission sin of omission sinful act sinfulness slang slip slipshod construction stiltedness suggestiveness taboo word tastelessness tort transgression trespass trip turgidity unaestheticism unaestheticness unbecomingness unchastity uncongeniality uncouthness undeservedness undeservingness undueness unentitledness uneuphoniousness unfavorableness unfitness unfittingness unfortunateness ungracefulness unjustness unlawfulness unmeetness unmeritedness unpropitiousness unrefinement unrighteousness unripeness unseasonableness unseemliness unsuitability unsuitableness untimeliness unutterable sin unwieldiness vandalism venial sin vice violation vulgar taste vulgarism vulgarity vulgarness wickedness wrong wrongdoing wrongfulness wrongness