doubtful adj.

1 feeling doubt

VERBS be, feel, look, seem, sound Eric was far from sure and Marion looked doubtful. | become | remain

ADV. extremely, very | a bit, a little, rather

PREP. about She was rather doubtful about the wisdom of eating the two-day-old food.

2 unlikely

VERBS be, look, seem | remain

ADV. extremely, highly, very Even if we could go, which is highly doubtful, John wouldn't be able to come with us. | increasingly | a bit, a little, rather, somewhat