WordWeb Online

1. Lacking the requisite qualities or resources to meet a task
   "inadequate training"; "the staff was inadequate";
   - unequal
    
2. Of insufficient quantity to meet a need
   "an inadequate income";
   - poor, short, jejune

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

Antonym: adequate