fall down flat

Переводы
потерпеть фиаско
His plans to start a new business fell down flat.
Его планы начать новый бизнес потерпели фиаско.
Определения
To suddenly lose one's balance and land on the ground, typically in a horizontal position; can also be used figuratively to describe a plan or idea that fails completely.
Слова
fall

глагол
падать
down

наречие
вниз
flat

наречие
плашмя