There are several synonyms for the term "not to purpose". Some of them include "inefficient", "unproductive", "futile", "pointless", "unsuccessful", "futile", "fruitless" and "inconclusive". These words are widely used to describe situations where an action or task fails to achieve the intended result or has no clear purpose or outcome. Whether it's a business plan that fails to generate profits or an experiment that produces inconclusive results, the term "not to purpose" can be applied to a variety of scenarios. Thus, having a grasp of different synonyms for the term can help to avoid repetition and convey the intended meaning more effectively.