blocker
Americannoun
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a person or thing that blocks.
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Football. a player whose assignment or special skill is blocking.
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Biochemistry. a substance that inhibits the physiological action of another substance, as the beta blocker propranolol that interferes with neurotransmitters in the sympathetic nervous system.
noun
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a person or thing that acts as a block
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physiol an agent that blocks a physiological function, such as the transport of an ion across an ion channel
Etymology
Origin of blocker
Middle English word dating back to 1200–50; see origin at block, -er 1
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
“I really thought that could have been a blocker, and I want to make sure it’s not,” he said.
From The Wall Street Journal • May 21, 2026
Burke is a solid run blocker — Pro Football Focus ranked him ninth at his position and he started 30 games at right tackle in college.
From Los Angeles Times • Apr. 25, 2026
If you try to change protocol while the ad blocker is enabled, you’ll get this:
From Salon • Mar. 13, 2026
In her review of gender services in Northern Ireland, Baroness Cass said that Northern Ireland was set to be a research site within the puberty blocker trial.
From BBC • Feb. 10, 2026
He could hit like a locomotive and was a devastating blocker.
From "October Sky" by Homer Hickam
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.