unsure

As an adjective unsure

is uncertain.

As a noun speculation is

the process of thinking or meditating on a subject.

As adjectives the difference between unsure and unassured

is that unsure is uncertain while unassured is not assured.

As adjectives the difference between diffident and unsure

is that diffident is (archaic): lacking confidence in others; distrustful while unsure is uncertain.

As adjectives the difference between problematic and unsure

is that problematic is posing a problem; difficult to overcome or solve while unsure is uncertain.

As a noun problematic

is (chiefly|in the plural) a problem or difficulty in a particular field of study.

As adjectives the difference between nervous and unsure

is that nervous is (obscure) of a piece of writing: forceful, powerful while unsure is uncertain.

As adjectives the difference between unpredictable and unsure

is that unpredictable is unable to be predicted while unsure is uncertain.

As a noun unpredictable

is an unpredictable thing.

As adjectives the difference between unsure and confused

is that unsure is uncertain while confused is unable to think clearly or understand.

As a verb confused is

past tense of confuse.

As adjectives the difference between improbable and unsure

is that improbable is not likely to be true while unsure is uncertain.