WordWeb Online

1. Nervous and unable to relax
   "a constant fretful stamping of hooves";
   - antsy [N. Amer, informal], fidgety, itchy, restless, on edge, keyed-up, twitchy [informal]
    
2. Habitually complaining
   "a fretful child";
   - querulous, whiney, whiny

See also: anxious, complaining, complaintive, nervous, queasy, tense, uneasy, unquiet