"light, feathery stuff," 1790, apparently a variant of floow "wooly substance, down, nap" (1580s), perhaps from Flemish vluwe, from French velu "shaggy, hairy," from Latin vellus "fleece," or Latin villus "tuft of hair" (see velvet). OED suggests fluff as "an imitative modification" of floow, "imitating the action of puffing away some light substance." Slang bit of fluff "young woman" is from 1903. The marshmallow confection Fluff dates to c.1920 in Massachusetts, U.S.
"to shake into a soft mass," 1875, from fluff (n.). Meaning "make a mistake" is from 1884, originally in theater slang. Related: Fluffed; fluffing.
: Show me an actor that never fluffed a line