The antonyms for the phrase "person's full intent and purposes" can vary depending on the context in which it is used. However, some possible antonyms include indecisiveness, ambiguity, vagueness, uncertainty, doubt, and hesitation. If a person's intentions and purposes are unclear or uncertain, it can lead to confusion and miscommunication. It is important to have clarity and conviction in one's intentions and purposes, especially in professional and personal relationships. Being clear about what one wants and why can help build trust and facilitate effective communication. In contrast, vagueness and uncertainty can lead to misunderstandings and mistrust.