夙しゅく夜や

noun, adverb

from morning till night; day and night; always

Literary or archaic expression for continuous effort or state throughout the day and night. In modern Japanese, 朝から晩まで or 日夜 are more common.

• 彼かれは夙しゅく夜や、研けん究きゅうに励はげんだ。