the morning after (sleeping together)
Archaic noun referring specifically to the morning after a couple has spent the night together. Not used in modern Japanese; the concept is now expressed with phrases like 一夜を共にした翌朝.
In classical waka poetry, there are poems that express the sorrow of 'the morning after.'
Archaic kanji spelling for the reading のちのあした; the reading のちのあさ is also recorded but rare.
Compound of 後 (のち, 'after') and 朝 (あした/あさ, 'morning'). The reading あした is an older form for 'morning' that survives in classical contexts.