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to yearn for (someone, something); to miss
彼女は故郷の日々を懐かしんだ。
She fondly recalled the days she spent in her hometown.
亡き祖母を懐かしんで、墓を訪れた。
Yearning for his late grandmother, he visited her grave.
過去を懐かしむ人は、しばしばそれを美化する。
People who miss the past often romanticize it.