What is mwah or muah?

"Mwah" or "muah" are onomatopoeic expressions commonly used to represent the sound of a kiss. They are often used in text messages or social media to convey affection, love, or gratitude in a playful and informal manner. People might use these expressions to sign off a message or reply to someone in a way that conveys a friendly kiss, similar to using an emoji like the "kiss face" or "heart" emoji. The spelling "mwah" or "muah" may vary depending on personal preference, but they generally communicate the same warm sentiment.