Corrupt officials enrich themselves through graft.
Tips
usage
Almost always appears as 中饱私囊 ('to pocket [funds] mid-transit') - the standard idiom for an official skimming public money. 中饱 means 'middleman skimming'; 私囊 is 'private purse'. Standalone 饱私囊 is a shortened form.
memory
Picture money flowing from the public coffers (公) to its destination - but a corrupt middleman fills (饱 'fill to fullness') his private bag (私囊) along the way.
