A family name that is generally passed down from generation to generation (via males of the family in Western culture). Women, traditionally (but not quite so much these days) often adopt the surname of the man they marry.
In modern culture it's fine for a male to adopt the females surname (though not that common), for couples to hyphenate their existing surnames into a new surname eg. if mary jones marries john smith they may join their surnames to be jones-smith or... possibly, it's fine to just create a whole new name (also not that common). Most commonly it is fine for each person to keep their own surnames and then fight when the children come along as to whose surname the children will get.
The thing that comes out of your mouth on those occassions when you really try hard to say 'nice' (with out an Errrr... in front of it) but your brain will not let you.
You go to your friends place to check out their new interior design... it's all leopard print with feature walls of hot pink with purple dots. They tell you they did it themselves and ask you what you think. You try hard (really hard) to keep a straight face and say 'nice' but instead Surgleyfonk slips out. example exaggerated to clarify