Antonyms of adj unsubstantiated

1 sense of unsubstantiated

Sense 1
uncorroborated, unsubstantiated -- (unsupported by other evidence)

INDIRECT (VIA unsupported) -> supported -- (sustained or maintained by aid (as distinct from physical support); "a club entirely supported by membership dues"; "well-supported allegations")

Similarity of adj unsubstantiated

1 sense of unsubstantiated

Sense 1
uncorroborated, unsubstantiated -- (unsupported by other evidence)
       => unsupported (vs. supported) -- (not sustained or maintained by nonmaterial aid; "unsupported accusations")