Which of the following terms can imply a specific use for a particular purpose?

The term "AD HOC" refers to something that is created or done for a specific purpose or situation, often without consideration for wider application. It is commonly used in various contexts such as project management, committees, or approaches that are tailored for a particular case or need. This specificity is what distinguishes "AD HOC" as it implies that the solution or decision is made specifically for that instance, rather than being a general or permanent solution.

In contrast, the other terms listed do not carry the same implication of being specifically tailored for a particular purpose. "ALTER EGO" refers to a second self or another persona, often used in legal contexts. "AD NAUSEAM" describes something that continues to the point of annoyance or excess, generally in reference to repetition. "AD INFINITUM" means 'to infinity' and signifies something that continues endlessly without a specific endpoint.