blocker

Definitions

A person or thing that prevents or obstructs progress or movement.

A player in sports such as football whose primary role is to obstruct opponents.

A substance or agent that prevents a specific biological or chemical process.

Examples

The lack of funding is the primary blocker preventing the team from starting the new project.

I need to install a pop-up blocker on my browser to stop those annoying advertisements.

Synonyms

obstacle hindrance impediment barrier obstruction bottleneck deterrent

Antonyms

facilitator enabler catalyst promoter advancer helper accelerator