na-adjective, noun
Literary or formal word for great distance, both physical and abstract. Rare in modern conversation; more common equivalents are 遠い or 遥か.
遼遠の地に思いを馳せる。
I let my thoughts wander to a distant land.
その計画の実現はまだ遼遠だ。
The realization of that plan is still far off.