Where a person is prevented from acting (or not acting) according to their free will, by threats or force of another, it is said to be under duress.
Contracts signed under duress are voidable and, in may places, you cannot be convicted of a crime if you can prove that you were forced or threatened into committing the crime (although this defence may not be available for serious crimes).
Duress can be in regards to threatened physical harm or economic duress.
In Brown v United States, Justice Holmes wrote that: "Detached reflection cannot be demanded in the presence of an uplifted knife".
REFERENCES:
Brown v United States 256 US 335 (1921)