applicator vs spray gun

applicator and spray gun both are nouns.

Word	Noun	Adjective	Verb	Adverb
applicator	Yes	No	No	No
spray gun	Yes	No	No	No

As nouns, spray gun is a hyponym of applicator; that is, spray gun is a word with a more specific, narrower meaning than applicator:

applicator: a device for applying a substance
spray gun: an applicator resembling a gun for applying liquid substances (as paint) in the form of a spray

Other hyponyms of applicator include flux applicator, paintbrush.

applicator (noun)	spray gun (noun)
a device for applying a substance	an applicator resembling a gun for applying liquid substances (as paint) in the form of a spray