expression, ichidan verb
cleanse oneself; purify oneself
Often used in religious or ritual contexts, such as before entering a shrine, or metaphorically for spiritual purification.
神社に入る前に、手水舎で身を清める。
Before entering the shrine, I purify myself at the purification fountain.
滝に打たれて身を清める修
There is a training practice of standing under a waterfall to cleanse oneself.