Synonyms and related words :
ad lib, disability, disablement, extemporaneousness, imbecility, improvisation, inability, inadequacy, incapability, incapacitation, incapacity, incompetence, incompetency, inefficiency, ineptitude, infancy, inferiority, insufficiency, lack of preparation, legal incapacity, minority, nonpreparation, nonpreparedness, planlessness, unfitness, unfittedness, unpreparedness, unqualification, unqualifiedness, unreadiness, unsuitability, unsuitableness, unsuitedness, vulnerability, wardship