self-doubt (n.)

• apprehension
• diffidence
• distrust
• distrustfulness
• doubt
• doubtfulness
• dubiety
• dubiousness
• misgiving
• mistrust
• question
• scruple
• scrupulousness
• self-depreciation
• self-distrust
• self-effacement
• skepticism
• suspicion
• suspiciousness
• uncertainty
• wariness