WordWeb Online

1. Weak in willpower, courage or vitality
   - namby-pamby [informal], gutless, spineless
    
2. Lacking interest, significance or impact
   "He was a wishy-washy man with hardly a mind of his own";
   - insipid, jejune
    
3. Lacking in vibrancy, colour, force

See also: lame, lameo [informal], meh [informal], uninspiring, uninteresting, weak

Encyclopedia: Wishy-washy