Humism Pyrrhonism agnosticism agonize over all-overs anxiety apprehension apprehensiveness awake a doubt be at sea be diffident be doubtful be dubious be possessive be skeptical be uncertain beat about call in question challenge concern confutability contest contestability controvertibility deniability diffidence disbelief disbelieve discredit disputability dispute disquiet distrust distrustfulness doubtful doubtfulness dubiety dubiousness dubitancy fear feel unsure flounder fluctuate foreboding greet with skepticism grope half believe half-belief harbor suspicions have reservations hesitate hesitation in doubt incertitude incredulity irresolution leeriness misdoubt misgive misgiving mistrust mistrustfulness puzzle over qualm qualmishness query question questionableness raise a question refutability reservations scepticism scoff scoffing scruple scrupulousness self-doubt shadow of doubt skepticalness skepticism smell a rat suspect suspicion suspiciousness thrash about throw doubt upon total skepticism treat with reserve unbelief uncertainty vacillate wariness waver wonder wonder whether worry