A person who has a happy on the outside but sad and depressed on the inside. They often make the best friends, are bad at sports and tend to spend most of their time on the couch.
Mersô is commonly used to someone who's marvelous at playing piano, incredibly sexy and/or have a very hairy chest. Someone who's able to impregnate anyone is also called a Mersô. A girl that look like Keith Emerson shall be called "Mersô Girl" and you shall make a song about her. Another common use of Mersô is when you reffer to someone with the ego at the size of the Wembley Stadium.
"Hey guys, check out this! I took a picture at the Love Beach!"
"Haha...your Mersô!"
"Guys, I looked to a girl and she got pregnant."
"Hohoho, you're such a Mersô."
"Guys, I played Bach concerts in piano without arms jumping from a plane with flying sharks!"
"Whoa! That's so Mersô."
The pairing of President Nicolas Sarkozy of France and Chancellor Angela Merkel of Germany. They have a healthy personal relationship, while managing two of Europe's biggest economies at the same time.