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blocker

American  
[blok-er] / ˈblɒk ər /

noun

  1. a person or thing that blocks.

  2. Football. a player whose assignment or special skill is blocking.

  3. 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.


blocker British  
/ ˈblɒkə /

noun

  1. a person or thing that acts as a block

  2. physiol an agent that blocks a physiological function, such as the transport of an ion across an ion channel

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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.

See Examples For:

Medics whisked him to safety, gave him a pain blocker, and placed him in a bed with a recessed, plush mat that molded to his body.

From Slate ● Sep. 22, 2026

Crabb: He’s been, in my mind, the top blocker for the U.S. the last four or five years.

From Los Angeles Times ● Jul. 11, 2026

Dame Hilary Cass says puberty blocker trial is "essential"

From BBC ● Jun. 22, 2026

“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

He could hit like a locomotive and was a devastating blocker.

From "October Sky" by Homer Hickam

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