Someone with louche taste is decadent and flashy. It’s one thing to wear gold around your neck as jewelry, but louche to have all your teeth capped in the precious metal just for the heck of it.
Louche is an adjective that describes something “of questionable taste or morality" but is also kind of attractive. It comes from the French louche, which also means “squinting,” and that word comes from the Latin lusca, meaning “one-eyed.” Imagine a louche pirate with an eye patch that you just can't turn away from. It's pronounced like a little kid trying to say "loose," like "loosh." You can also use louche in place of words like decadent, shady, and sinister.