pipe dream
US /ˈpaɪp ˌdrim/
UK /ˈpaɪp ˌdrim/

1.
mrzonka, złudzenie
an unrealistic hope or fantasy
:
•
His plan to become a millionaire overnight is just a pipe dream.
Jego plan, by z dnia na dzień zostać milionerem, to tylko mrzonka.
•
Getting a promotion without working hard is a pipe dream.
Awans bez ciężkiej pracy to mrzonka.