1. (n.) Neglect or failure to do something required by propriety or duty; exclusion\.

2. (n.) That which is omitted or is left undone.

Sisyphean labor abbreviation abridgment absence arrearage atrocity bad policy balk ban bar barring beggary bevue blank blockade blue-penciling bowdlerization boycott breach break cancellation censoring censorship chasm circumscription crime crime against humanity culpa culpable negligence deadly sin debarment debarring defalcation default defect defectiveness deficiency deficit deletion delinquency demarcation deprivation dereliction destitution disconformity discontinuity disregard dropping drought editing elimination embargo endless task enormity erasure error evil exception excision excluding exclusion expurgation failure false move false step famine fault felony gap genocide guilty act heavy sin hiatus imperfection impolicy impoverishment impropriety inadmissibility inadvertence inadvertency inattention incompleteness indiscretion inexecution inexpedience inexpediency inexpiable sin iniquity injunction injury injustice inobservance interval laches lack lacuna laissez-faire lapse lapsus calami lapsus linguae laxity laxness leaving out lockout loose ends loose thread looseness maladministration malefaction malfeasance malpractice malum minor wrong misadministration misconduct miscue misdeed misdemeanor misdirection misfeasance misgovernment misguidance mishandling mismanagement misrule missing link misstep mortal sin narrowing need neglect neglectfulness negligence nonaccomplishment nonachievement nonadherence nonadmission noncompliance nonconformance nonconformity nonconsummation nondischarging nonexecution nonfeasance nonfulfillment noninterference nonobservance nonperformance nonrestriction offense omitting outage outrage overlook overlooking oversight peccadillo peccancy permissiveness poor stewardship preclusion preterition procrastination prohibition rejection relegation remissness repudiation restriction rough edges shortage shortcoming shortfall sin sin of commission sin of omission sinful act skip skipping slackness slight slip slipup starvation striking stumble taboo tort transgression trespass trip ullage unfulfillment unobservance unrigorousness unutterable sin venial sin want wantage work of Penelope wrong wrong step wrongdoing