Complaints or grievances; or to make complaints; also the plural of beef meat.
From Old French 'buef,' from Latin 'bos' (cattle). The slang meaning 'complaint' originated in 1800s America, possibly from 'having a beef with someone' meaning conflict.
The slang 'beef' for a complaint might come from carnival workers or boxers—it's unclear, but what's cool is how one word split into completely different meanings: livestock meat vs. personal grudges, and slang 'beefed up' meaning strengthened, as if adding more beef adds more strength.
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