**Explanation:**

The word "uncouth" is an adjective that is used to describe someone or something that is lacking in grace or refinement. It often implies a lack of manners, sophistication, or social polish. The correct answer is option B - "ungraceful."

Here is a breakdown of the other options and why they are incorrect:

a) **Rough** - While someone who is uncouth may also be rough in their behavior or mannerisms, the term "rough" does not fully capture the lack of grace or refinement that is implied by "uncouth."

c) **Slovenly** - This term refers to a lack of neatness or tidiness, often in regards to personal appearance or the state of one's surroundings. It does not directly relate to the lack of grace or refinement that is associated with being uncouth.

d) **Dirty** - This term refers to something that is unclean or soiled. While someone who is uncouth may also be dirty in their habits or personal hygiene, it is not the primary characteristic associated with being uncouth.

In summary, "uncouth" is best described as someone who is ungraceful in their behavior and lacks refinement or social polish.