Wordnet 3.0
ADJECTIVE (1)
1. 
 lacking definite form or limits; 
- Example: "gropes among cloudy issues toward a feeble conclusion"- H.T.Moore- Example: "nebulous distinction between pride and conceit"[syn: cloudy, nebulose, nebulous]
The Collaborative International Dictionary of English v.0.48:
Nebulose \Neb"u*lose`\, a.
   Nebulous; cloudy. --Derham.
   [1913 Webster]
WordNet (r) 3.0 (2006):
nebulose
    adj 1: lacking definite form or limits; "gropes among cloudy
           issues toward a feeble conclusion"- H.T.Moore; "nebulous
           distinction between pride and conceit" [syn: cloudy,
           nebulose, nebulous]