IPA: /ˈɡɑːɡlə/
KK: /ˈɡɑrɡlər/
A person who gargles, which means to wash the throat and mouth with a liquid that is held in the back of the throat and made to vibrate.
After brushing his teeth, he became a gargler to soothe his sore throat.
Gargler → It is formed from "gargle" (from Middle French *gargouiller*, meaning to bubble or to make a noise in the throat) and "-er" (meaning a person who). A gargler is a person who gargles, or makes a bubbling sound in the throat while rinsing with liquid.
Think of someone making a bubbling sound in their throat while rinsing — that's what a gargler does.