One can read about it in those louche tomes

a louche, chain-smoking Lebanese in a safari pantsuit

he was named as one of the louche uncles

When a man walks aimlessly and for pleasure he is called a flaneur; a certain louche glamour attaches to the word.

listening to a louche character with a thick moustache

The louche Playboy rubs elbows with the staid Time.

The boundaries he pushes are only partly for our benefit; his chameleon love affair with the frisson of the louche

His current self was considerably more louche

in an atmosphere of louche decadence, the business and cultural elite linger like models or gawp like voyeurs as they stand around a swimming pool