blocker

Etymology

From Middle English blocker, blokker, bloker, blokkere, equivalent to block + -er.

noun

1. Agent noun of block (“obstruct or prevent”); something that blocks something else.
   1. (sports) One who blocks or impedes the movement of an opponent.
   2. (computing) One who prevents another user from contacting them electronically.
      Likewise, any connections shared between your child (the blocker) and the user being blocked will also be broken. 2013, Elizabeth Laugeson, The Science of Making Friends
   3. (computing) An application that stops / impedes unauthorised access to a programme.
      an ad blocker
      a content blocker
   4. (computing) A bug or issue that prevents software from being released.
   5. (marketing) A gatekeeper who refuses the marketer access to the person they wish to contact.
      Sometimes your sales progress skids to a halt. We've all met more blockers than we'd care to. Some are assigned by the company to filter services […] 1992, Joan Guiducci, Joan Guiducci's power calling, page 49
   6. (biology, medicine) Any of various medications that block (inhibit) the activity of a chemical messenger or its receptors, such as cardiac conduction modifiers (e.g., alpha-blockers), gastric acid inhibitors (H₂ histamine blockers), puberty blockers, and others.
      Blockers can optimize the development of preferred physical characteristics. In trans girls, blockers initiated prior to the development of male secondary sex characteristics will effectively prevent voice deepening, skeletal enlargement, and penile enlargement. 2014, Laura Erickson-Schroth, Trans Bodies, Trans Selves: A Resource for the Transgender Community, Oxford University Press, page 443
   7. A close-fitting rectangular glove worn by a goalie in multiple forms of hockey.
   8. (poker) A blocker bet.
   9. (card games) A playing card, needed by one player, that is held by another.
2. A person who blocks (stretches or moulds) hats.
   Because in 1937 Benjamin is still an apprentice, he remains bound to the Eastern Finland Hat Factory. […] Benjamin now does much of the same work as the master cutters and blockers and enjoys their grudging approval of his skills. 2019, John B. Simon, Strangers in a Stranger Land, page 218