unbackable

the politician's claim was completely unbackable by any evidence.

scientists consider the ancient theory unbackable with current technology.

his unbackable argument collapsed during the debate.

the unbackable proposition was quickly rejected by the committee.

she presented an unbackable case for her unusual hypothesis.

the unbackable assertion lacked any scientific foundation.

legal experts deemed the lawsuit unbackable in court.

his unbackable stance on the issue cost him credibility.

the unbackable thesis could not withstand critical examination.

critics found the director's unbackable claims about the film laughable.

the unbackable allegation was dismissed without prejudice.

many consider the economic prediction unbackable given market volatility.