The article made several unsubstantiated claims.

The journalist unsubstantiated the claims made by the politician.

The ghostly figure appeared to be unsubstantial, fading in and out of view.

She danced unsubstantially across the stage.

The unsubstantiation of his claims led to his downfall.

The unsubstantiality of his claims was evident to everyone.

The artist explores the unsubstantialities of modern society.

The company unsubstantialized its claims with insufficient evidence.

He unsubstantializes his dreams by not taking any action.

She is unsubstantializing her dreams by focusing on practical goals.