(transitive) To create a blockade against.

A high-explosive bomb used for the purposes of demolishing extensive areas, such as a city block.

(colloquial) A stupid person. / A sideshow performer who hammers nails or similar items through his or her nostril into the nasal cavity; human blockhead.

To perform as a human blockhead. / (rare) To behave in a stupid manner.

(computing) a piece of software that prevents pop-up advertisements from being displayed

(physics) the increased resistance observed at low temperatures in some semiconductor devices

(pharmacology) A blocking agent, one of a class of drugs used to treat hypertension and control the rate at which the heart beats.

A sturdy military fortification, often of concrete, with gunports. / A reinforced building from which to control hazardous operations, such as an explosion or a rocket launch.

plural of blocker

(sports) One who blocks or impedes the movement of an opponent. / (computing) One who prevents another user from contacting them electronically.