unfounded (adj.)
- airy
- apparent
- apparitional
- autistic
- baseless
- bottomless
- chimeric
- deceptive
- delusional
- delusive
- delusory
- dishonest
- dreamlike
- dreamy
- empty
- erroneous
- fallacious
- false
- fantastic
- garbled
- gratuitous
- groundless
- idle
- illusional
- illusionary
- illusive
- illusory
- imaginary
- inauthentic
- inconclusive
- indecisive
- mendacious
- misleading
- ostensible
- phantasmagoric
- phantasmal
- phantom
- seeming
- specious
- spectral
- spurious
- supposititious
- unauthentic
- uncalled-for
- uncertified
- unconfirmed
- uncorroborated
- undetermined
- unestablished
- unfixed
- unjustifiable
- unjustified
- unproved
- unproven
- unreal
- unreliable
- unsettled
- unsound
- unsubstantial
- unsubstantiated
- unsupportable
- unsupported
- untenable
- untested
- untried
- untrue
- untruthful
- unverified
- unwarranted
- vain
- visionary
