set gun is a noun meaning "a gun that is set to fire on any intruder that comes in contact with the wire that sets it off". It carries one recorded sense.
a gun that is set to fire on any intruder that comes in contact with the wire that sets it off
Definitions, synonyms and semantic relations for set gun come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.