Diktat (noun)

1. An order or decree imposed by someone in power without any possibility of negotiation or discussion.
2. A harsh settlement imposed by a conquering power on a defeated nation.

Origin:

From german diktat, from latin dictatum something dictated, from dictare to dictate.

Examples:

1. The new government issued a diktat banning all forms of protest.
2. The dictator's diktat was accepted without any opposition.
3. The defeated nation had to accept the terms of the diktat imposed by the conqueror.
4. The diktat was a harsh measure to enforce the new laws.
5. The diktat was a non-negotiable ultimatum that was accepted under duress.