doubtful (adj.)
- absurd
- agnostic
- ambiguous
- arguable
- borderline
- chancy
- clouded
- confutable
- conjectural
- conscienceless
- contestable
- contingent
- controversial
- controvertible
- corrupt
- corrupted
- criminal
- crooked
- dark
- debatable
- deniable
- devious
- dishonest
- dishonorable
- disputable
- disreputable
- distrustful
- doubtable
- doubting
- dubious
- dubitable
- equivocal
- evasive
- felonious
- fishy
- fraudulent
- hazy
- hesitant
- hesitating
- iffy
- ill-gotten
- immoral
- implausible
- improbable
- inconceivable
- incredible
- incredulous
- indecisive
- indefinite
- indeterminate
- indirect
- insecure
- insidious
- leery
- mistakable
- mistrustful
- moot
- obscure
- open
- precarious
- preposterous
- problematic
- queasy
- questionable
- questioning
- refutable
- ridiculous
- rocky
- rotten
- sceptical
- scrupulous
- shady
- shaky
- shameless
- shifty
- shy
- sinister
- skeptical
- slippery
- speculative
- suppositional
- suspect
- suspecting
- suspicious
- tall
- thick
- thin
- tottery
- touch-and-go
- treacherous
- tricky
- unbelievable
- uncertain
- unclear
- unconscientious
- unconscionable
- unconvinced
- unconvincing
- undecided
- undependable
- underhand
- underhanded
- unearthly
- uneasy
- unethical
- ungodly
- unhealthy
- unimaginable
- unlikely
- unpredictable
- unprincipled
- unpromising
- unreliable
- unresolved
- unsafe
- unsavory
- unscrupulous
- unsettled
- unsound
- unstable
- unsteady
- unsure
- unthinkable
- untrusting
- untrustworthy
- vacillating
- vague
- wary
Oh, rather give me commentators plain,
Who with no deep researches vex the brain;
Who from the dark and doubtful love to run,
And hold their glimmering tapers to the sun.
