What is the suffix for refraction?

There isn't a specific suffix for "refraction". "Refraction" itself is the noun form of the verb "refract".

If you want to describe something related to refraction, you might use the following:

* refractive: This is an adjective meaning "relating to or causing refraction."

* refractivity: This is a noun meaning "the tendency of a substance to refract light."

For example, you might talk about the refractive index of a material, or the refractivity of water.