If a person or thing is swallowed up by something, they disappear into it so that you cannot see them any more. He headed back towards the flea market and was quickly swallowed up in the crowd Weeds had swallowed up the garden
If one thing is swallowed up by another, it becomes part of the first thing and no longer has a separate identity of its own. During the 1980s monster publishing houses started to swallow up smaller companies
If something swallows up money or resources, it uses them entirely while giving very little in return. A seven-day TV ad campaign could swallow up the best part of £50,000 Farmers could see a quarter of their income swallowed up by the interest rate rise