1. not based on fact or evidence; without foundation or justification

Examples

• The rumors about the company’s bankruptcy proved to be completely unfounded.
• Her fears about the safety of the neighborhood were unfounded.
• The accusations against the teacher were unfounded and quickly dismissed.
• Critics called his claims unfounded and lacking in evidence.
• The police investigation showed that the complaints were unfounded.
• His optimism about the project’s success seemed unfounded given the circumstances.