a leap in the dark
US /ə liːp ɪn ðə dɑːrk/
UK /ə liːp ɪn ðə dɑːrk/
1.
an act or decision whose consequences are unknown and potentially dangerous, but which is undertaken anyway
:
•
Starting a new business without a clear plan is often a leap in the dark.
•
She decided to move to a new country without a job offer, which was a leap in the dark.