What does 夜更かし mean?
夜更かし is a Japanese noun meaning “staying up late, keeping late hours” in English. It is written as 夜更かし in kanji, よふかし in hiragana, and yofukashi in romaji. This word is part of JLPT N1 vocabulary.
Example sentence
今夜は好きなだけ夜更かししていいぞ。
Tonight you can stay up as late as you like.