WordWeb Online

1. Lacking the requisite qualities or resources to meet a task
   "inadequate training"; "the staff was inadequate"
   - unequal
    
2. Not sufficient to meet a need
   "an inadequate income"
   - poor, short

See also: adequacy, adequateness, deficient, inadequately, inadequateness, incapable, incompetent, insufficient, lacking, short-handed, short-staffed, undermanned, understaffed, unequal to, unsatisfactory, wanting

Antonym: adequate