KANYE WEST debuted a new song over the weekend that he wrote about KIM KARDASHIAN, and it carries the very romantic title, "Perfect [B-word]".  Although Kanye uses the ACTUAL B-word.  Unfortunately, we don't have audio.  Kanye debuted it at a club in New York City after he and LEONARDO DICAPRIO rolled into the joint at about 1:30 Sunday morning.  And no one has posted it online yet.

But a source says, "[He raps] verses about his search for the perfect woman and how he has now found the 'perfect [b-word]."  It also contains references to Kim's,  "famous curves". 

And just in case there was any confusion, Kanye later Tweeted,  "I wrote the song . . . about Kim."  There's no word if or when Kanye plans to release it.