noun
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.
古典の和歌には「後の朝」の切なさを詠んだものがある。
In classical waka poetry, there are poems that express the sorrow of 'the morning after.'
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.