If an individual cannot be subdued, they are considered to be:

When describing an individual who cannot be subdued, the term "indomitable" is particularly fitting. It conveys the sense of someone who cannot be overcome or brought under control, exhibiting an unwavering strength and resilience. The root of the word itself implies a certain invincibility in spirit or determination, suggesting that no matter the circumstances, this individual remains unconquerable.

In contrast, the other terms imply a willingness to submit or conform in some way. For instance, "docile" and "yielding" suggest a degree of compliance or ease in being led or controlled, which clearly does not align with the concept of being unable to be subdued. "Rebellious," while it suggests resistance, doesn't encapsulate the broader notion of an unbreakable spirit as effectively as "indomitable." Thus, "indomitable" accurately describes someone who remains resolute and unyielding in the face of challenge.