The word "defaultant" typically refers to someone who fails to make payments or fulfill their obligations. Some synonyms for this word include nonpayer, delinquent, and defaulter. Other related words might include debtor, owing, and arrears. These terms all describe situations where someone has failed to meet their obligations, typically in relation to financial or legal matters. While these words may have slightly different connotations or applications, they are often used interchangeably to describe someone who has defaulted on their responsibilities. Whether you're talking about unpaid debts, missed deadlines, or other forms of noncompliance, these synonyms can help you describe the situation in concise and accurate terms.