to suffer a bitter experience or defeat; to taste disappointment (idiomatic, somewhat formal).
昨年の決勝でチームは苦杯を喫した。
The team suffered a bitter defeat in last year's final.
新製品は市場で苦杯を喫し、企業は戦略を見直した。
The new product had a disappointing reception in the market, and the company revised its strategy.
彼は交渉で苦杯を喫したが、それを学びに変えた。
He suffered a bitter setback in the negotiations, but turned it into a lesson.