conjecture

Noun

• reasoning that involves the formation of conclusions from incomplete evidence

• a message expressing an opinion based on incomplete evidence

• a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence)
  • speculations about the outcome of the election
    
  • he dismissed it as mere conjecture
    

Verb

• to believe especially on uncertain or tentative grounds
  • Scientists supposed that large dinosaurs lived in swamps
    

Related words

• Synonyms: 
  guess , supposition , surmise , surmisal , speculation , hypothesis , speculate , theorize , theorise , hypothesize , hypothesise , hypothecate , suppose