noun
bitter experience; bitter defeat; ordeal
Almost exclusively used in the set phrase 苦杯をなめる (to have a bitter experience; to suffer a bitter defeat). The literal meaning 'bitter cup' is rare outside this idiom.
See also: 苦杯をなめる
彼は選挙で苦杯をなめた。
He suffered a bitter defeat in the election.
交渉の末、苦杯をなめることになった。
After the negotiations, we ended up having a bitter experience.
Also means 'bitter experience' and appears in the similar phrase 苦汁をなめる, but 苦杯 is more strongly associated with defeat or humiliation.
Compound of 苦 (bitter, painful) and 杯 (cup, sake cup). The phrase 苦杯をなめる (to drink a bitter cup) is a metaphor for enduring a painful or humiliating experience.