ad lib disability disablement disqualification extemporaneousness imbecility improvisation inability inadeptness inadequacy inaptitude inaptness inattentiveness incapacitation incapacity incompetence incompetency indexterity ineffectiveness ineffectuality inefficiency ineptitude ineptness infancy inferiority insufficiency lack of preparation legal incapacity maladjustment maladroitness mediocrity minority nonpreparation nonpreparedness pedestrianism planlessness rustiness skill-lessness thoughtlessness unaptness uncleverness undeftness undexterousness undextrousness unfitness unfittedness unintelligence unpreparedness unproficiency unqualification unqualifiedness unreadiness unschooledness unskillfulness unsuitability unsuitableness unsuitedness untrainedness unworkmanlike vulnerability wardship