unfeasible
/ʌnˈfiːzɪbəl/Definitions
1. adjective
not capable of being done or accomplished, because of some inherent difficulty or impossibility
“The plan to build a skyscraper in the middle of the ocean was deemed unfeasible due to the immense logistical challenges.”
2. noun
a situation or proposal that is not feasible
“The team’s research revealed that the project’s budget was a major unfeasibility that needed to be addressed.”