The word frou-frou came up last night at the French conversation group and I thought I’d find out more about it.

In French, frou-frou [fʁu.fʁu] refers to a rustling sound, as of silk fabric. It also means rustle, frilly, frilliness or frills. Related words include froufrouter (to swish, rustle), and froufroutement (rustle, scroop, swish) [source]. It is of imitative origin [source].

Scroop? Apparently it means a rustling sound like that produced from friction between silk fibres; to produce a harsh scraping, grating sound, as of friction; to make sounds such as of a chair on the floor or chalk on a blackboard; or to produce a rustling sound, like that from friction between silk fibres, and is of imitative origin [source].

Frou-frou [ˈfɹuːfɹuː] was borrowed into English and means:

• A rustling sound, particularly the rustling of a large silk dress.
• Liable to create the sound of rustling cloth, similar to 19th-century dresses.
• Highly ornamented, overly elaborate; excessively girly.
• Unimportant, silly, useless.
• To move with the sound of rustling dresses [source].

It has also been borrowed into Portuguese as frufru, where it means overly decorated or colourful, or a ruff, rustle or rustling (of fabrics) [source], and into Spanish as frufrú (rustle, rustling (of fabrics)) [source]

Other ways to say rustle in French include:

• froissement [fʁwas.mɑ̃] = rustle, rustling, crumpling, wrinkling (of paper, fabric, etc)
• bruissement [bʁɥis.mɑ̃] = rustling (of paper), murmuring, swish
• bruire [bʁɥiʁ] = to rustle, rattle, roar, murmur, whisper, hum, swish
• froisser [fʁwa.se] = to crease, wrinkle, rustle, ruffle (feathers), strain (a muscle) hurt, offend, take offence [source].

If you want to talk about rustling cattle or other animals, the word voler (to steal, rob, fly) is used in French, and the French equivalent of to rustle up (to prepare quickly) is préparer en vitesse (“to prepare / make hurriedly”).