squirter vs water gun

squirter and water gun both are nouns.

Word	Noun	Adjective	Verb	Adverb
squirter	Yes	No	No	No
water gun	Yes	No	No	No

As nouns, squirter and water gun are synonyms defined as:

squirter and water gun: plaything consisting of a toy pistol that squirts water

Other synonyms of squirter include squirt gun, water pistol.

squirter (noun)	water gun (noun)
plaything consisting of a toy pistol that squirts water	plaything consisting of a toy pistol that squirts water