oneoff

One-off is an adjective and a noun that describe something that happens, is made, or is produced only once and is not repeated. As an adjective, it describes items or events that are not part of a regular sequence, such as a one-off special edition or a one-off payment. As a noun, a one-off refers to a single instance of something.

Originating in manufacturing jargon, the term implies something produced off the regular production line, i.e., not part of ongoing production. Spelling typically uses a hyphen: one-off; occasionally seen as oneoff or written as one off in running text, but the hyphenated form is standard in British English, while American usage often favors one-time or single-use instead.

Common applications include manufacturing (a one-off production run), entertainment (a one-off concert or special edition), finance (a one-off payment or tax adjustment), and software or data tasks (a one-off script or data migration performed only once). In journalism and policy, one-off can describe exceptions or infrequent measures.

One-off emphasizes singularity and non-recurrence, sometimes implying novelty or exception rather than routine. It should not be used to describe repeated or planned events unless explicitly intended as a single occurrence. When precision is needed, terms such as one-time, single-use, or special edition may be more appropriate depending on the region and context.