What does Matchy - matchy refer to?

[McRoy]

I am somewhat confused, about the term "Matchy-matchy on this site. It might well be it has been defined elsewhere, but I was not able to find a thread relating to a definition. Does this term suggest one should not coordinate colors in one's dress or have items match? From a personal standpoint, I prefer when things match and or compliment each other in my attire. This does not mean mindlessly conforming to so called traditional rules, but for me the aesthetic of a well coordinated outfit, speaks volumes about the wearer in a positive light. Looking like one simply put on the first thing at hand seems a trifle lower class to me. I can see no issue with wearing matching tie and hose flashes on plain hose to compliment one's tartan. If that is Matchy-matchy, then I for one am all for it.