WordWeb Online

1. Filled with shade
   "we sat on rocks in a shadowy cove"
   - shady, shadowed, umbrageous
    
2. Lacking clarity or distinctness
   "shadowy figures in the gloom"
   - dim, faint, vague, wispy
    
3. Lacking in substance
   "strange fancies of unreal and shadowy worlds"; "dim shadowy forms"
   - wraithlike

Derived forms: shadowiest, shadowier

See also: indistinct, insubstantial, shaded, shadow, shadowiness, unreal, unsubstantial