Unsubstantiated (adjective)

Not supported or backed up by evidence or proof.

Origin:

From un- (not) + substantiated (supported by evidence).

Examples:

1. The accusations against him were unsubstantiated and could not be proven.
2. The story was full of unsubstantiated claims and was not credible.
3. The theory was unsubstantiated and was not accepted by the scientific community.
4. She had many unsubstantiated suspicions about her co-workers.
5. The rumor was unsubstantiated and was not true.