WordNet records no synonym and no antonym for firewall. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
(colloquial) the application of maximum thrust
“he moved the throttle to the firewall”
(computing) a security system consisting of a combination of hardware and software that limits the exposure of a computer or computer network to attack from crackers; commonly used on local area networks that are connected to the internet
Synonyms, antonyms and the broader and narrower relations for firewall come from Princeton University’s WordNet. Full sources and licences.
a fireproof (or fire-resistant) wall designed to prevent the spread of fire through a building or a vehicle