penance; austerity; difficult practice
Primarily a Buddhist term for rigorous spiritual training or ascetic practice, often involving hardship. Can also refer more broadly to any difficult undertaking or ordeal.
彼は山にこもって難行を続けた。
He secluded himself in the mountains and continued his penance.
この修行は
This training is truly a difficult practice.
the hard way; path of difficult practice
penance; austerities; hardship
From 難 (difficult) + 行 (practice, conduct). The term is used in Buddhist contexts to refer to arduous spiritual practices.