indeterminate
in-de-ter-mi-nate
adjective
Not precisely known, established, or defined; uncertain or vague in extent.
"The length of the delay was indeterminate."
Thesaurus
Synonyms: indeterminable, undeterminable, undetermined, open-ended, cost-plus, equivocal, ambiguous, inconclusive, racemose
Antonyms: determinate