What prefix has the same meaning as word bad?

There isn't a single prefix that directly means "bad" in the same way that the word "bad" does. However, several prefixes convey a sense of negativity, imperfection, or deficiency, which could be considered related to "bad":

* Mal-: This prefix is often used to indicate something bad, harmful, or wrong. Examples: malnourished, malfunction, malpractice.

* Dis-: This prefix can indicate negation, opposition, or absence, often resulting in a negative connotation. Examples: dishonest, dislike, disadvantage.

* Un-: This prefix often indicates the opposite or absence of something, making it negative in many cases. Examples: unhappy, unfriendly, unhealthy.

* Mis-: This prefix suggests error, failure, or wrongness. Examples: misinterpret, misjudge, mistake.

It's important to remember that these prefixes don't always have a negative meaning, and their specific connotation depends on the context of the word they are attached to.