speculative

1. ADJ. A piece of information that is speculative is based on guesses rather than knowledge.

• The papers ran speculative stories about the mysterious disappearance of Eddie Donagan.
  

2. ADJ. Someone who has a speculative expression seems to be trying to guess something about a person or thing.

• His mother regarded him with a speculative eye.
  

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2. not based on fact or investigation; 

• "a notional figure of cost helps in determining production costs"; 
• "speculative knowledge"
• = notional

3. showing curiosity; 

• "if someone saw a man climbing a light post they might get inquisitive"; 
• "raised a speculative eyebrow" 
• = inquisitive, wondering, questioning

.... Thesaurus/WordNet 3.0