Synonyms of uncertain in English:

uncertain


See definition of uncertain

adjective

1‘the environmental effects of the project are uncertain’

SYNONYMS
unknown, undetermined, unsettled, unresolved, unsure, pending, in the balance, in limbo, up in the air, debatable, open to question, in doubt
unpredictable, unforeseeable, incalculable, speculative
unreliable, untrustworthy, undependable, risky, chancy
informal dicey, hairy, iffy
British informal dodgy
ANTONYMS

certain, settled, predictable

2‘the uncertain weather meant that passengers needed to pack a pullover or two’

SYNONYMS
changeable, variable, varying, irregular, fitful, unpredictable, unreliable, unsettled, unstable, erratic, fluctuating
informal peaky
rare changeful, fluctuant

3‘Edward was a little uncertain about the decision’

SYNONYMS
unsure, doubtful, dubious, undecided, unresolved, indecisive, irresolute, hesitant, wavering, vacillating, oscillating, equivocating, vague, hazy, unclear, ambivalent, in two minds, on the horns of a dilemma, torn
informal iffy, blowing hot and cold, on the fence
ANTONYMS

certain, sure

4‘I gave her an uncertain smile’

SYNONYMS
hesitant, hesitating, tentative, halting, faltering, unsure, unconfident, diffident, doubtful
ANTONYMS

confident