This is a scary topic.  And names and definitions can be super confusing, which makes it even more frightening.
But great news!  Knowledge makes things way less scary, so let's break some of this down before we get started:

​

Islam (in and of itself) is just a religion.  Nothing more.  But...

​

Islamism is the ideology that seeks to impose any version of Islam over society.

​

Islamism is, therefore, theocratic extremism.

​

Jihadism is the use of force to spread Islamism.

​

Jihadist terrorism is the use of force that targets civilians to spread Islamism.