doubtverb
whether
I doubt whether her motives for donating the money are entirely pure.
I doubt whether this will work, but let's try anyway.
He doubted if the plan could work in practice.
I doubt if anyone knows where the key to this lock is.
SMART Vocabulary: related words and phrases
Uncertainty
amorphous
be neither fish nor fowlidiom
blurringly
blurry
circumstantial
indeterminate
indeterminately
insecurely
insecurity
interrogatively
murky
shakiness
shallowly
slippery
spec
squishy
wavery
wifty
wishy-washy
you never knowidiom