WordWeb Online

1. (used of persons or artifacts) marked by independence and creativity in thought or action
   "an imaginative use of material";
   - inventive
    
2. (of an idea or story) so exaggerated or ludicrous as to be improbable
   - farfetched, far-fetched
    
3. (of a theory or explanation) highly imaginative but unlikely and unconvincing
   "an imaginative excuse";
   - farfetched, far-fetched

See also: creative, implausible, originative, unlikely

Encyclopedia: Imaginative