Unspecified means not clearly stated, identified, or defined. When something is unspecified, the details are left vague or blank, either on purpose or by accident.

If a teacher announces “We'll have a quiz at an unspecified time next week,” students know a quiz is coming but don't know whether it's Monday or Friday. If a package is being delivered on an unspecified date, you know it's coming eventually, but you can't plan around when it will arrive.

Sometimes things are left unspecified deliberately. A contest might offer “an unspecified number of prizes” to keep things mysterious and exciting. Other times, unspecified details create frustration. If your parents say you can invite an unspecified number of friends to your birthday party, you might wish they'd just tell you the actual limit.

The word often appears in formal contexts like instructions, contracts, or announcements. When a form asks you to explain “unspecified reasons” for something, it means reasons that haven't been clearly spelled out. The opposite of unspecified is specified, which means clearly stated and defined, leaving no room for confusion.