Upper Middle Class - the very top layer of the middle class.

People who think nothing of spending $4.50 on a coffee, think getting change from $10 for a sandwich/loaf of sourdough or $20 from a cocktail is a great deal, are prone to saying "Oh, I looooove foreign films", are overeducated yet underskilled, can't cook anything except toast because they eat out three times a day, adore Steve Jobs, say words like "problematic" when they really mean "bad", describe the inhabitants of their preferred Developing World holiday destination as "such a beautiful people", whose parents pay their rent and who rarely "check" their own "privilege", complain of being "soooo busy" while they are freelancing at a cafe, are generally kidults, etc etc etc.

Unintended Mexican Children. Children of Mexican families that are obviously not wanted.

U Mad Corny (you're mad corny) the person you refer this to is silly, tried to tell a joke that failed, purposely does something to aggravate or please someone or purposely does something he/she knows will get a negative response.

UMC is internet slang for you my crush or u my crush

United Model Congress

The greatest club that ever lived.
Master debaters that congregate for several weekends a year to hangout, have coed sleepovers, and DEBATE!

Stands for Under Major Construction.