What is the opposite prefix of distinct?

The opposite prefix of "distinct" would depend on what aspect of "distinct" you want to negate. Here are a few options:

* Indistinct: This is the most direct opposite, meaning "not clear or definite." This is useful if you're talking about something that is difficult to discern or identify.

* Undistinct: While less common, this prefix also indicates a lack of distinction. It implies something that is not clear, defined, or unique.

* Non-distinct: This is a straightforward way to indicate the opposite of "distinct," implying something that is not separate or individual.

The best choice for the opposite prefix will depend on the specific context and what you want to emphasize.