also: とうかん
noun
night sweats; sweating during sleep
Refers to excessive sweating while sleeping, often associated with illness or fever.
風邪をひいて寝汗をかいた。
I caught a cold and had night sweats.
寝汗がひどくて、パジャマがびしょびしょになった。
My night sweats were so bad that my pajamas got soaked.
Rare kanji form, mainly used in medical contexts. Reading とうかん is restricted to this form.
汗 is general sweat, while 寝汗 specifically refers to sweat produced during sleep.
Compound of 寝 (ne, 'sleep') and 汗 (ase, 'sweat'). The reading ねあせ is a straightforward combination. The alternative kanji 盗汗 (tōkan) is a Sino-Japanese medical term.