On Thin Ice

Rooted in the very literal danger of skating or walking across a frozen river or lake where the ice hasn't fully hardened. Skating itself has deep roots in the Netherlands, where frozen waterways were historically used for winter travel, making the risk of thin ice a genuinely common, well-understood hazard. The American writer Ralph Waldo Emerson gave the phrase an early figurative outing in his 1841 essay "Prudence": "In skating over thin ice our safety is in our speed." The Oxford English Dictionary treats the phrase as a US colloquialism, with its earliest confirmed written use in this sense dating to 1871.