Muah is an expression with various meanings, and it is based of the sound one makes when exaggerating a kissing noise.
It is normally used online, because in real life you could easily just make the kissing noise itself.
The kissing noise can be a form of greeting or goodbye between friends.
Mostly girls and women use it when greeting each other, but male friends with a type of “bromance” relationship may use it for fun.
Another use is to give credit to someone, for example if they prepared you an extraordinary meal.
The credit doesn’t even have to go to a person. You could send a “muah” to a beautiful view or a fancy piece of clothing as well.
Some prefer the spelling “mwah”.
Apart from the expression, it is also a widely used acronym for “Make-Up And Hair”.
Many countries use kisses as a form of greeting, and as the internet developed, it saw need for an online version of the kiss as well.
A normal kiss will usually just make a smacking sound because of the tension of the lips, but if you add a continuous vocal sound to the kiss, you end up with the sound “muah”.
This is where the phonetic spelling of the term comes from.
As previously mentioned, kisses as a greeting is widespread in many countries, particularly kisses on the cheek.
However, not everyone is comfortable with actually giving a real kiss, therefore they will place their cheeks next to each other and say “muah” instead, indicating a kiss.
On communicating platforms such as Whatsapp and Messenger you can find a range of various “muah” emotes and gifs to send to friends and family.