What is the prefix of disbelief?

There isn't a single, commonly used prefix that means "disbelief". However, there are several prefixes that convey a similar concept, depending on the specific nuance you're aiming for:

* Dis-: This is the most common prefix for "not" or "lack of", and it's often used to express disbelief. For example: "disbelieve", "discredit", "disillusionment".

* Un-: Similar to "dis-", this prefix also denotes negation. You could use "unbelief" to express a lack of belief.

* In-: This prefix can also indicate a lack of something, but it often carries a stronger sense of being against or opposed to something. For example: "incredible" (not believable) or "inconceivable" (unimaginable).

Ultimately, the best prefix to use depends on the specific context and the meaning you want to convey.