excluder
/ˈɛkskˈluːdər/Definitions
1. noun
A device or mechanism that prevents something from entering or being included.
“The excluder on the water filter ensures that large particles are not allowed to pass through.”
2. noun
A person or thing that excludes or bars others from a place or opportunity.
“The excluder in the company’s hiring policy was criticized for discriminating against minority groups.”