blocker

Something or someone that impedes (for any reason) the flow of work. The work that is impeded can be our team’s own work or the work of one or more other teams. For clarity, work must be in a blocked state (i.e., impeded) to refer to something or someone as a blocker. If someone or something has the potential to block us, then such an entity would more properly be referred to as “potential blocker.” All dependencies are potential blockers.  All blockers are caused by the failed coordination of a dependency. Synonymous with impediment. See also dependency.