I.down1[美 daʊn, 英 daʊn]副down often appears as the second element of certain verb structures in English (back down, clamp down, tone down, etc). For translations, see the relevant verb entry (back, clamp, tone, etc).
While grocery shopping, the kids scarf down as many free samples as they can until the employee tells them that the samples are just incentives for people to buy.
Here's a relieving factoid to put your cravings in context: arthropods, the class of invertebrates including insects, millipedes and spiders, can scarf down way more junk food than you can.
The almost superhuman digestive systems of competitive eaters are put to the test each year as contenders scarf down as many hot dogs as they can in 10 minutes.