off a cliff

Littéralement « depuis [le sommet d’]une falaise ». De off et cliff.

off a cliff \ˈɒf ə klɪf\

1. En prenant des risques excessifs, sans se poser de questions, avec des conséquences potentiellement désastreuses.
   • (…) saying they were “so obsessed with a hard Brexit that they’re prepared to run the economy off a cliff and they don’t like the fact that Philip is pointing out that we will deservedly lose the next election if we do that”. — (The Guardian, Tory efforts to downplay cabinet rifts insult intelligence of voters, juillet 2017)