noun
Refers to sake heated to a lukewarm temperature, typically around 40°C, a popular serving style in colder months.
寒い日はぬる燗がおいしい。
On cold days, warmed sake is delicious.
この店ではぬる燗を頼む人が多い。
Many people order warmed sake at this restaurant.
Compound of ぬる (lukewarm) and 燗 (warming sake). The exact historical derivation is uncertain, but the term is conventionally associated with sake heated to a moderate temperature.