blocker

/ˈblɑkər/
noun
  1. A person or thing that prevents movement, progress, or action.
    • A pop-up ad blocker can make browsing the web much faster.
    • The fallen boulder was a huge blocker on the hiking trail.
    • In football, the offensive lineman is a key blocker for the runner.
  2. A substance or device that stops something from passing through.
    • The pipe's clog was a stubborn blocker of water flow.
    • She uses a sunscreen that is a strong UV blocker.
    • A noise blocker can help you sleep in a loud city.
Antonyms
What does "blocker" mean? | whatsthatwordmean | whatsthatwordmean