Synonyms: undeterminable, indeterminable
Definition: not capable of being definitely decided or ascertained
Similar words: indeterminate
Definition: not capable of being determined
Usage: the indeterminate number of plant species in the jungle
Similar words: unascertainable, undiscoverable
Definition: not able to be ascertained; resisting discovery
Similar words: unpredictable
Definition: unknown in advance
Usage: an unpredictable (or indeterminable) future