noun, noun or participle which takes 'suru'
penance; austerities; hardship
A yojijukugo referring to severe religious austerities or, by extension, any extremely difficult undertaking. Often used in Buddhist contexts for ascetic practices, but also figuratively for grueling efforts.
彼は難行苦行の末に悟りを開いた。
He attained enlightenment after severe austerities.
This project was truly a grueling ordeal.