Okay, so imagine you have a group of friends and you really like one of them. This friend is your "bestie", meaning they are your absolute favorite friend out of everyone.
Now think about a Rabbi, who is a leader in the Jewish religion. Sometimes, there is a Rabbi who is extra special to a group of people. They are like the "bestie" Rabbi, or the Rabbi that stands out as the most important and influential to that group.
This special Rabbi is called a "Rav Muvhak", which is a Hebrew term that means "distinguished Rabbi". It's like a title that says, "This Rabbi is the most important and respected among us".
So basically, a Rav Muvhak is a really important Rabbi who is like the "bestie" Rabbi to a certain group of people.