Flou: Softness, haziness, blurriness; also an adjective meaning foggy, fluffy, or indistinct. French; pronounced floo.
Flou is one of those French words that occasionally appear in fashion journalism—for example, in this Women's Wear Daily review of the designer Sophie Theallet's Fall 2010 collection, which Theallet showed at New York Fashion Week:
The lineup, said Theallet several days before the show, was about lost girlhood memories. Namely, “the first time you fell in love with a princess dress,” she said. “I tried to give that feeling to a grown-up woman.” And she did, but not with a lot of flou and frou; instead, her dresses were mostly short, done in tiny florals or soft blue and pink and green, and trimmed in velvet or leather.
And what is that rhyming noun, frou? Usually seen reduplicated (frou-frou), it's an onomatopoetic French word meaning "the rustling of silk." Here, though, it's used in its metaphorical sense to mean "excessive ornamentation."
Flou is also the name of an Italian bed manufacturer and an alternative rock/metal band in Paraguay. As far as I can tell, flou has no specific meaning in Italian or Spanish; in both cases, it may be a borrowing from French.