untriable
/ʌnˈtraɪəbəl/Definitions
1. adjective
Impossible or impractical to try or investigate; not capable of being tried or proved.
“The scientist concluded that the phenomenon was untriable with current technology.”
2. noun
A person or thing that is impossible or impractical to try or investigate.
“The untriable mysteries of the universe have long fascinated scientists and philosophers alike.”