1. the quality or state of being doubtful, uncertain, or open to question
2. the quality of being morally or ethically questionable; suspiciousness

Examples

• The dubiousness of his claims made everyone skeptical.
• There is some dubiousness about whether the evidence will hold up in court.
• The dubiousness of the company's financial practices led to an investigation.
• She expressed dubiousness about the plan's feasibility.
• The dubiousness surrounding the witness's testimony weakened the prosecution's case.
• He regarded the offer with considerable dubiousness.