I'm cheating a little, 'cause I may have heard the word "flâneur" before; but it came up twice in unrelated contexts on the same day, a month or so back, so I figured I'd mention it here.

To quote Wikipedia: "A flâneur is a detached pedestrian observer of a metropolis, a 'gentleman stroller of city streets', first identified by Charles Baudelaire."

The two occurrences I recently encountered:

Mr. Rose knew that something unusual was going on, he said, when the very first ad he received, after starting the column in 1998, began: "67-year-old disaffiliated flâneur picking my toothless way through the urban sprawl, self-destructive, sliding towards pathos, jacked up on Viagra and on the lookout for a contortionist who plays the trumpet."

--"Book Lovers Seek Lovers, Buttered or Plain," by Sarah Lyall, an article about the London Review of Books personals column.

And, from a Wikipedia article on a Degas painting called " Viscount Lepic and his Daughters Crossing the Place de la Concorde," this: "The Vicomte Lepic was an aristocrat, artist, and flâneur."