supposititious

Adjective

• based primarily on surmise rather than adequate evidence
  • theories about the extinction of dinosaurs are still highly conjectural
    
  • the supposed reason for his absence
    
  • suppositious reconstructions of dead languages
    
  • hypothetical situation
    

Related words

• Synonyms: 
  conjectural , divinatory , hypothetical , hypothetic , supposed , suppositional , suppositious