Kyūjitai form of 竜涎香 (“ambergris”)

“a hundred days of sermonizing, one fart” → a metaphor for how something that one has put great effort into can come to nothing after even a slight mistake, much as a hundred days of serious spiritual study can be lost to the winds

a futile endeavor, a brave but useless attempt

Traditional Chinese (Chinese written using traditional characters)

Simplified Chinese (Chinese written using simplified characters)