expression, godan verb (-su)
line one's own pockets; enrich oneself by abusing one's position
Used when someone in a position of trust or authority secretly profits at the expense of others or the organization. Strongly negative connotation.
その政治家は公金を使って私腹を肥やしていた。
That politician was lining his own pockets using public funds.
経理
It came to light that the accounting manager had been enriching himself with company money.