infeasible

形容词 infeasible:

1. not capable of being carried out or put into practice
   同义词：impracticable, unfeasible, unworkable

in.fea.si.ble

adj.（形容词）
Not feasible; impracticable:
办不到的；不能实行的：
例句：
a plan that turned out to be infeasible.
证明行不通的计划