Antonyms of adj unfounded

1 sense of unfounded

Sense 1
baseless, groundless, idle, unfounded, unwarranted, wild -- (without a basis in reason or fact; "baseless gossip"; "the allegations proved groundless"; "idle fears"; "unfounded suspicions"; "unwarranted jealousy")

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 unfounded

1 sense of unfounded

Sense 1
baseless, groundless, idle, unfounded, unwarranted, wild -- (without a basis in reason or fact; "baseless gossip"; "the allegations proved groundless"; "idle fears"; "unfounded suspicions"; "unwarranted jealousy")
       => unsupported (vs. supported) -- (not sustained or maintained by nonmaterial aid; "unsupported accusations")