on a razor's edge
US /ɒn ə ˈreɪzərz ɛdʒ/
UK /ɒn ə ˈreɪzərz ɛdʒ/
1.
in a very dangerous or precarious situation; at a point where a small change could have either a very good or very bad result
:
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The company's finances are on a razor's edge after the recent losses.
•
The negotiations were on a razor's edge, with either side ready to walk away.