decay, rot, remain in seclusion

古い木は朽ちて、やがて土に返る。

The old wood decays and eventually returns to the earth.

長年の雨風で、柱が朽ちかけている。

The pillar is beginning to rot from years of rain and wind exposure.

彼は田舎で朽ちるまで静かに暮らした。

He lived quietly in the countryside, remaining in seclusion until the end of his days.