The word "uwu" is a representation of a face with closed eyelids, expressing happiness. The letter "u" represents the closed eyes, and the letter "w" represents the kawaii mouth. Previously it was written differently, specifically "uu", a gesture somewhat typical of Asia, in countries such as Japan and South Korea.
There are many variations of uwu and owo, including and OwO, UwU, and OwU, among others.
Many talk about it being oriental, reminiscent of Japanese anime characters, but apart from Japan, it is often used a lot in Korea. It is usually used by the young as well as the elderly, since it is something that has been planted to survive and not something new, it has been with us for many years.
uwu can also mean that you are flirting with the person you are talking to, either uwu itself or a similar one like 7w7. It is also often used to respond to a compliment, so it may be an expression used with a person or in response to another person.
uwu is not one of the oldest expressions, it is derived from uu and variegated which is used as in OO (eyes open) or >. <(eyes closed). Already in Asia they are starting to benefit a lot from uwu and the expansion is due to the great acceptance in other continents.
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