Englishsceptical
adjective
they were sceptical about the Treasury's forecast of inflation dropping to 3 per cent:
dubious, doubtful, having reservations, taking something with a pinch of salt, doubting, questioning;
cynical, distrustful, mistrustful, suspicious, disbelieving, misbelieving, unconvinced, incredulous, hesitant, scoffing;
pessimistic, defeatist;
informal iffy;
rare Pyrrhonist, minimifidian.
▷antonyms certain, convinced; optimistic.
sceptical Oxford Dictionary of English