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to refuse; to reject; to dismiss; to turn down; to decline
to inform; to give notice; to ask in advance (and get approval); to get permission
to ask leave; to excuse oneself (from)
申し出を断るのは難しかった。
It was hard to refuse the offer.
親に断ってから旅行に行った。
I let my parents know before going on the trip.
彼女は丁寧に依頼を断ってきた。
She politely refused.