Feather your nest
Meaning
Enrich oneself, often at others' expense.
Usage
Used critically about self-serving behavior.
Origin & History
Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.
Birds lining nests with feathers for comfort.
17th-century English idiom with moral overtones.