na-adjective, noun
far ahead; long way to go; distant
A yojijukugo used for a goal, journey, or task that is still far off. Often carries a slightly literary or formal tone.
目標達成まではまだ前途遼遠だ。
We still have a long way to go before achieving our goal.
この研究の完成は前途遼遠である。
The completion of this research is far off.