Wiktionary
n. A small brass gong used in Korean folk music
Wikipedia
The kkwaenggwari is a small flat gong used primarily in folk music of Korea. It is made of brass and is played with a hard stick. It produces a distinctively high-pitched, metallic tone that breaks into a cymbal-like crashing timbre when struck forcefully. It is particularly important in samul nori and pungmul, although it is also used in other genres.
The instrument's name is probably onomatopoetic for the sound the instrument produces, "ggwaeng-ggwaeng" (hangul: 꽹꽹). An alternate name is swe.
This gong is struck with a wooden mallet to produce a sharp attention commanding sound. The instrument is commonly used in folk performing arts in Korea, including shamanic music, dance, mask dance drama, and is the lead instrument in pungmul.