beefeater, n.¹ — Green’s Dictionary of Slang

beefeater n.¹

[stereotype of the beef-eating British + SE beefeater, a Yeoman of the Guard, one of London’s tourist icons]

(US) an Englishman or -woman.

1628		F. Greville Sidney 109: We conquered France, more by such factions and ambitious assistances than by any odds of our Bows, or beef-eaters as the French were then scornfully pleased to terme us [F&H].
1675		F. Fane Love in the Dark IV i: Nay, prithee good Beef-eater, stay a little.
1960, 1975		Wentworth & Flexner DAS.
1983		Maledicta VII 25: The English, probably in this century, came to be called beefeaters, probably from the dual influence of the fame of English roast beef and the name of the warders of the Tower of London, the Beefeaters.