noun
continuous decline; on the wane
Describes a situation or entity that is steadily and seemingly irreversibly declining. Often used in formal or written contexts.
その産業は衰退一途をたどっている。
That industry is on a path of continuous decline.
地方経済は衰退一途で、打開策が見つからない。
The local economy is in steady decline, and no solution has been found.
Compound of 衰退 (decline) and 一途 (one road, single course), literally 'the one road of decline.'