‌Context & Objective: In Shia Islamic jurisprudence, legal acts are traditionally classified strictly as either contracts (ʿaqd) or unilateral acts (iqāʿ), each possessing distinct legal implications. However, categorizing certain acts within this binary classification remains contentious among scholars. Guarantee (ḍamān) exemplifies such ambiguity, as Shia jurists are divided regarding whether it must strictly constitute a contract or can also be recognized as a unilateral act. While most jurists advocate for its exclusive contractual nature, a minority supports its validity as a unilateral act. The purpose of this research is to analyze critically and systematically these divergent viewpoints and determine whether ḍamān inherently belongs to a specific legal category or whether its classification depends on contextual factors. Specifically, the research addresses the question: Is the classification of ḍamān necessarily confined to a contractual form, or can it legitimately function as a unilateral act under specific conditions?
 ‌Method & Approach: Employing a doctrinal research methodology, this study conducts a comprehensive analytical review of primary sources and scholarly arguments within Imāmī jurisprudence. The study systematically investigates foundational theoretical justifications supporting both dominant (contractualist) and minority (unilateralist) perspectives.
 ‌Findings: The research reveals substantial limitations in the prevailing argument that confines guarantee (ḍamān) exclusively to a contractual form. Critical analysis demonstrates that the jurisprudential justifications presented by contractualists do not convincingly preclude the legitimacy of guarantee as a unilateral act. Rather, the findings indicate that both conceptual frameworks—contractual and unilateral—are jurisprudentially plausible and internally consistent within Shia legal theory. The authors' hypothesis is thus affirmed, emphasizing the conditionality and flexibility in classifying ḍamān based on the specific nature of the parties' expressions and intentions.
 ‌Conclusion: The study concludes that the classification of guarantee (ḍamān) within Shia Islamic jurisprudence should not be rigidly restricted to a single category. Instead, its form is contingent upon the practical and intentional context in which it occurs. When mutual consent and explicit bilateral agreement are evident, ḍamān properly takes the form of a contract. Conversely, when initiated independently by one party without requiring acceptance, it legitimately constitutes a unilateral act. This conclusion not only resolves the theoretical ambiguity surrounding ḍamān but also aligns jurisprudential interpretation with practical legal realities, thereby enriching and diversifying the conceptual understanding of legal acts within Shia jurisprudence.