What is post-modern?

There's someone I think I could call a friend (we've not met in 'meatspace', nor spoken directly, but I appreciate him) who's on holiday in Dubia. He described it as the most post-modern city in existence.

The most recent description I heard of postmodern was the word 'unprincipled'. Postmodern seems to mean that "whatever works for you is OK, as long as I can do anything that works for me". To me, that would imply a city of readily available vices, each to suit a different taste, but kept clean and neat in appearance. Certianly it would seem that if golf is your vice that it will be fulfilled in many and pleasant ways.

Being an Arab city, I doubt it's the overt den of vice that somewhere like New Orleans was reputed to be. However some cultures have an ability to turn a blind eye for paying customers. I wonder if this could be the case, or whether he really meant that they've built a city from scratch in the last 40 years, no expense spared.