The Korean language has a rich collection of slang and colloquialisms, including the most commonly used term for friend, "chingu," which means close or intimate person. Other slang terms for friends include "hyeong," "noona," and "unnie." The use of slang reflects the changing attitudes and values of Korean society, particularly among young people. Technology has played a significant role in popularizing slang, and its future is likely to be shaped by ongoing changes in society and technology. Non-Koreans can use "chingu" appropriately by understanding the cultural context and being aware of gender and age differences.