Not affording certainty
In doubt or dispute
Liable to more than one interpretation
Of dubious character
Marked by lack of firm decision or commitment; of questionable outcome
Capable of or liable to change
Following no predictable pattern
Doubtful in mind
He was silent, uncertain how to answer.
She'd seemed uncertain and scared, though.
She walked towards her quarters, uncertain why his departure bothered her.
She held up her arm, uncertain how to release it.
She entered the bedroom quietly to see Toby awake and trying to get an uncertain Lankha to play with his stuffed animals.