unusable

Unusable is an adjective describing something that cannot be used for its intended purpose in a given context. It implies that the item fails to meet the needs of its users under ordinary conditions.

Common causes include poor design, lack of accessibility, excessive cognitive load, technical failures, or environmental constraints that prevent operation or safe use. A product may be unusable for a particular user group even if it works for others, highlighting the role of user characteristics in usability.

There is a distinction between temporary unusability, such as a device being offline or a service outage, and inherent or pervasive unusability, where the design prevents any reasonable use by most users. Context matters, including the user’s goals, environment, and available resources.

Assessment relies on usability research methods such as task-based testing, heuristic evaluation, and accessibility audits. Metrics include task success rate, time to complete, error rate, and user satisfaction. In safety-critical or high-stakes settings, additional criteria may emphasize reliability, clarity of feedback, and fail-safe behavior.

Remediation involves user-centered redesign, clearer feedback, better error handling, improved accessibility, updated documentation, and adherence to standards. Design practices such as progressive disclosure, consistent interaction patterns, and responsive design can reduce unusability. Standards and guidelines, including accessibility frameworks, help ensure wider usability across diverse users and contexts.

Unusable products can lead to user frustration, reduced adoption, and safety or financial consequences for organizations that fail to address usability.