1. lacking or indicating lack of confidence or assurance

- uncertain of his convictions

- moving with uncertain (or unsure) steps

- an uncertain smile

Similar word(s): ambivalent, doubtful, dubious, groping, incertain, unsure

2. not established beyond doubt; still undecided or unknown

- an uncertain future

- a manuscript of uncertain origin

- plans are still uncertain

Similar word(s): indefinite, indeterminate, undetermined

3. not established or confirmed

Similar word(s): unsealed

4. not certain to occur; not inevitable

- everything is uncertain about the army

- the issue is uncertain

Similar word(s): chancy, flukey, fluky, iffy, contingent, unpredictable

5. subject to change

- the weather is uncertain

Similar word(s): variable, changeable, unsettled

6. not consistent or dependable

- an uncertain recollection of events

- a gun with a rather uncertain trigger

Similar word(s): undependable, unreliable

7. ambiguous (especially in the negative)

- she spoke in no uncertain terms

Similar word(s): ambiguous

Sentences with uncertain as an adjective:

- Tomorrow's weather is uncertain.