Smuggling compartments were hidden, hollow spaces in starships and other vehicles made to hide contraband from customs searches.
The Millennium Falcon was modified with smuggling compartments. Han Solo, Chewbacca, Luke Skywalker, C-3PO, R2-D2, and Obi-Wan Kenobi utilized these compartments during the rescue of Leia Organa to evade the stormtroopers scouring the freighter. However, they were well aware they likely could not hide from a scanning crew's intensive sweep of the ship. So they ambushed the crew when they came on board and lured the Stormtroopers standing sentry immediately to overpower them as well to use their armor as a disguise