staple gun vs staplegun

staple gun and staplegun both are nouns.

Word	Noun	Adjective	Verb	Adverb
staple gun	Yes	No	No	No
staplegun	Yes	No	No	No

As nouns, staple gun and staplegun are synonyms defined as:

Other synonyms of staple gun include tacker.

staple gun (noun)	staplegun (noun)
a hand-held machine for driving staples home	a hand-held machine for driving staples home