effective

ephemeral, transitory

religious (committed to the practice of religion)

voluntary, of one's own initiative, of one's own accord

perpetual, permanent, everlasting

modern

secondary

“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

(weaponry) an intercontinental ballistic missile

(weaponry) Synonym of 大陸間弾道ミサイル (tairikukan dandō misairu, “intercontinental ballistic missile”)