What is the suffix for word inevitable?

The word "inevitable" doesn't have a suffix. It's a complete word on its own.

Let's break it down:

* Root: "inevit"

* Suffix: None

The word "inevitable" is formed by adding the prefix "in-" to the root word "evitable." The prefix "in-" means "not" or "the opposite of," so "inevitable" means "not avoidable" or "certain to happen."