Avoir le couteau sous la gorge is a French idiom that literally to “to have a knife under the throat” and means “to be under the gun”.
Avoir le couteau sous la gorge
to be under the gun

Example sentence
Pierre a certainement le couteau sous le gorge en ce moment. Il doit avoir assez d’argent pour subvenir aux besoins de sa famille et payer ses dettes.
Pierre is definitely under pressure now. He needs to have enough money to support his family and pay his debts.
More ways of saying “to be under pressure in French:
- Être sous pression (to be under pressure)
- Avoir de la pression (to have pressure)
- Subir la pression (to deal with pressure)
- Se sentir sous pression (to feel under pressure)