incapable 9 Associations

unable (similar term) incompetent (related term) capable (antonym)

inefficient 11 Associations

uneconomical (similar term) wasteful (similar term) incompetent (related term) ineffective (related term) uneffective (related term) ineffectual (related term) efficient (antonym)

unqualified 11 Associations

quack (similar term) incompetent (related term) ineligible (related term) qualified (antonym)