na-adjective
impracticable; infeasible; unworkable; impossible to carry out
Describes plans, methods, or ideas that cannot be put into practice due to practical constraints.
その計画は予算が足りず、実行不可能だと判断された。
The plan was judged impracticable due to insufficient budget.
理論上は正しいが、現時点では実行不可能な案だ。
It's correct in theory, but it's an unworkable idea at present.
Compound of 実行 (じっこう, 'execution') + 不可能 (ふかのう, 'impossible').