mountain ascetic; Shugendō practitioner
Refers to a follower of Shugendō, a syncretic mountain ascetic tradition. Often associated with yamabushi.
See also: 修験道
Shugendō practitioners undergo severe training in the mountains.
That mountain ascetic often stands under a waterfall.
修験道 is the name of the syncretic religion itself, while 修験者 is a practitioner of it.
From 修験 (shugen, 'mountain ascetic practice') + 者 (sha, 'person'). The term is directly associated with Shugendō.