Merriam-Webster Collegiate Dictionary - riffle

 I. verb  (~d; riffling)  Etymology: 2~  Date: 1754  intransitive verb  1. to form, flow over, or move in ~s  2. to flip cursorily ; thumb ~ through the catalog  transitive verb  1. to ruffle slightly ; ripple  2.  a. to leaf through hastily; specifically to leaf (as a stack of paper) by sliding a thumb along the edge of the leaves  b. to shuffle (playing cards) by separating the deck into two parts and riffling with the thumbs so the cards intermix  3. to manipulate (small objects) idly between the fingers  II. noun  Etymology: perhaps alteration of ruffle  Date: 1785  1.  a. a shallow extending across a streambed and causing broken water  b. a stretch of water flowing over a ~  2. a small wave or succession of small waves ; ripple  3.  a. any of various contrivances (as blocks or rails) laid on the bottom of a sluice or launder to make a series of grooves or interstices to catch and retain a mineral (as gold)  b. a groove or interstice so formed  4. a cleat or bar fastened to an inclined surface in a gold-washing apparatus to catch and hold mineral grains  5. ~ (I)  a. the act or process of shuffling (as cards)  b. the sound made while doing this