blocker
n. countablen. something that stops you from making progress on a task or project. In a work setting, it is often a problem you need someone else to solve before you can continue.
n. an obstacle or impediment that prevents a process or task from advancing. In agile project management, it refers specifically to an external dependency or issue that halts a team member's workflow.
The lack of a budget is a major blocker for our project.
During the morning meeting, the developer mentioned that the server downtime was a blocker for the new software release.
Identifying potential blockers early in the development cycle allows the project manager to reallocate resources and prevent a total stall in the production pipeline.
Commonly used in professional and technical environments to describe workflow interruptions.