inconclusive (adj.)
- contradictory
- fallacious
- faulty
- feeble
- flawed
- flimsy
- groundless
- illogical
- inauthentic
- incongruous
- inconsequent
- inconsequential
- inconsistent
- indecisive
- indefinite
- indeterminate
- insubstantial
- invalid
- irrational
- loose
- open
- poor
- reasonless
- self-contradictory
- senseless
- unauthentic
- uncertain
- uncertified
- unconfirmed
- unconnected
- uncorroborated
- undetermined
- unestablished
- unfinished
- unfixed
- unfounded
- unproved
- unproven
- unreasonable
- unresolved
- unscientific
- unsettled
- unsound
- unsubstantial
- unsubstantiated
- unsupported
- untested
- untried
- unverified
- weak
