Here are a few options for a description for the WordPress post_tag “違法行為” (Illegal Activities) in Traditional Chinese, ranging from concise to more descriptive:

**Option 1: Concise and Direct (Best for general use)**

> 與法律相悖的行為。 (Behaviors that go against the law.)

**Option 2: Slightly More Descriptive**

> 描述觸犯法律、違反法規的行為。 (Describes actions that break the law or violate regulations.)

**Option 3: Emphasizing Consequences**

> 涉及違反法律和可能導致法律後果的行為。 (Activities that involve breaking the law and potentially leading to legal consequences.)

**Option 4: Focusing on the Nature of the Tag Itself (for SEO considerations)**

> 標記涉及非法活動、違法行為的文章。 (Tags articles that involve illegal activities, illegal behaviors.)

**Option 5: Adding a Broader Context (If desirable)**

> 有關違反法律和法規、不被社會所接受的行為的討論和資訊。 (Discussions and information about behaviors that violate laws and regulations and are not accepted by society.)

**Which option is best depends on your blog’s context and needs.** I would generally recommend **Option 1** or **Option 2** for their brevity and clarity. You should also consider:

* **Your Audience:** Are they legal professionals, students, or the general public? Tailor the language accordingly.
* **Blog Content:** What kind of content will be tagged with this term?
* **SEO:** While the description is less important than the tag itself for SEO, a well-written description can help clarify the tag’s meaning to search engines, especially if you are using it in context.

Remember to select the description that best fits your overall content strategy. Good luck!