water gun 
noun North American
A water pistol.As soon as you see the younger cat approaching the older one ‘in that way,’ squirt him with a water gun or plant sprayer or make a loud noise using a whistle or an empty soda can with six or seven pennies inside....
- There wasn't anything wrong with Kris, I mean, besides the fact that he continuously squirted us with a water gun as children.
- A boy about ten years of age ran to a group of three boys and squirted water from his water gun, wetting them.