leery (adj.)

• agnostic
• cagey
• careful
• cautious
• chary
• distrustful
• doubtful
• doubting
• dubious
• guarded
• incredulous
• mistrustful
• questioning
• sceptical
• scrupulous
• shy
• skeptical
• suspecting
• suspicious
• uncertain
• unpersuadable
• untrusting
• wary