fire extinguisher vs asphyxiator

fire extinguisher and asphyxiator both are nouns.

Word	Noun	Adjective	Verb	Adverb
fire extinguisher	Yes	No	No	No
asphyxiator	Yes	No	No	No

As nouns, fire extinguisher and asphyxiator are synonyms defined as:

fire extinguisher and asphyxiator: a manually operated device for extinguishing small fires

Other synonyms of fire extinguisher include extinguisher.

fire extinguisher (noun)	asphyxiator (noun)
a manually operated device for extinguishing small fires	a manually operated device for extinguishing small fires