Select the most appropriate meaning of the given idiom.
Black sheep

The correct option is Disreputable.

Idiom Breakdown:
The idiom "Black sheep" is used to describe a member of a family or a group who is regarded as a disgrace or who has a bad reputation. In a flock of white sheep, a black sheep stands out and was historically considered less desirable, leading to the figurative meaning of someone who is disreputable or does not conform to the respectable standards of the group.

Analysis of the Options:
- Naive: This means showing a lack of experience, wisdom, or judgment. This is incorrect.
- Miscreant: This refers to a person who behaves badly or breaks the law. While a black sheep may behave poorly, the term specifically highlights being a source of embarrassment or having a bad reputation within a group, rather than necessarily being a criminal.
- Disreputable: This means not respectable in character or appearance, which directly matches the definition of a "black sheep" as someone who brings shame or is looked down upon by their family or community.
- Intelligent: This means having or showing intelligence, which is unrelated to the idiom.

Therefore, the most appropriate meaning of the given idiom is Disreputable.