to be U.K'd (you-kayed) is to be invited into someones house and immediately or soon after entering the premises being asked to leave for no reason what-so-ever.
"all was going good until the bitch U.K'd me as soon as i got into the door"
Acronym for Double Income, No Kids, Unbelievable Mortgage. Describes young hard-working marrieds (or a pair of faggots) who are deferring having children whilst they plough all their money into a very large housing loan. See also D.I.N.K.
Look at that huge mansion; a couple of D.I.N.K.U.M s there.