inure

新渡戸稲造の武士道を読んでいます。COURAGE, THE SPIRIT OF DARING AND BEARINGの章から引用します。

Parents, with sternness sometimes verging on cruelty, set their children to tasks that called forth all the pluck that was in them. “Bears hurl their cubs down the gorge,” they said. Samurai’s sons were let down the steep valleys of hardship, and spurred to Sisyphus-like tasks. Occasional deprivation of food or exposure to cold, was considered a highly efficacious test for inuring them to endurance. Children of tender age were sent among utter strangers with some message to deliver, were made to rise before the sun, and before breakfast attend to their reading exercises, walking to their teacher with bare feet in the cold of winter; they frequently—once or twice a month, as on the festival of a god of learning,-—came together in small groups and passed the night without sleep, in reading aloud by turns.

"inure" は以前契約書をよく読む機会があった時に「効力を生じる」意味で使われていたことを思い出しましたが、上記の例での意味を確認します。

・Oxford English Dictionary: (formal) to make somebody/yourself get used to something unpleasant so that they/you are no longer strongly affected by it: The prisoners quickly became inured to the harsh conditions.
・Collins Dictionary: (usually fol. by to) to accustom to hardship, difficulty, pain, etc.; toughen or harden; habituate: inured to cold

困難な事などに慣れさせる意味で使われるのですね。私が知っていたのは (esp of a law, etc) to come into operation; take effectの用法の方でした。