Which is not a characteristic of a multiparty system?

The correct answer is:

They are usually dictatorships.

A multiparty system, in politics, is a system where multiple political parties postulate in the national election, and all of them have the capacity of winning. This possibility of more than one party or leader have similar chances to win, eliminates the concept of dictatorship, which is only one leader with total control of government and imposing decisions without anyone else's rule.

they are unusually dictatorships.