Based on social status:
* ignoble: This is the most direct opposite, meaning "not noble" or "of low birth or character."
* unnoble: Similar to "ignoble," but often implies a lack of nobility rather than a specific social standing.
Based on character:
* ignoble: This can also be used to describe someone with low moral standards or character.
* base: Describes something or someone lacking in honor, virtue, or refinement.
* vile: This is a strong word that implies extreme moral depravity.
* debased: Indicates something that has been lowered in quality or value, often morally.
* ignoble: This can also be used to describe something that is not worthy of respect or admiration.
Based on actions:
* ignoble: Can also refer to actions that are dishonorable or unworthy.
* unworthy: This implies something or someone that is not deserving of respect or honor.
Ultimately, the best opposite of "noble" will depend on the specific context and the nuance you wish to convey.