Describe or explain what is meant when we say "mung mouth"?

Answer 1

I believe that the term that you are referring to is "Mun Mouth." This term refers to an individual who is not very talkative, and specifically who is very good at keeping secrets or confidential information. It is good to have some friends who are "mun mouth," as you can discuss private information with them and you know that they will not disclose it to others, However, be very careful, as "mun mouth" friends and people are very hard to find, and are "few and far in between!"