Irish pennant
n.— «The term “Irish pennant” derives from the Royal Navy during the time of sailing ships. It was a loose or untidy end of a line. In Navy and Marine Corps parlance today, an Irish pennant is a loose thread on a uniform, for which you get gigged at inspection.» —“Irish Pennants” by Jack Kelly Irish Pennants May 5, 2005. (source: Double-Tongued Dictionary)
Further reading
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