“John le Carré” was the pseudonym of writer David Cornwell, who was working as a member of Her Majesty’s secret service when his first novels were published, requiring that he disguise his identity. He was advised by his publisher to choose a name with “two Anglo-Saxon monosyllables, like Chunk-Smith” as a false name, but chose instead the oddly French “le Carré.” Carré means “square” or “squared” in French, and is indeed sometimes a family name, but used with le seems a bit strange, coming across as “John the Square.”
This whole story of the writer’s name has an uncanny resonance with the word spy itself, which, while it has a chunky Anglo-Saxon monosyllabic quality, actually comes to English from French.
But, perhaps unsurprisingly, hiding behind the French word’s identity is a slightly unusual Germanic background—unusual for a language that directly descended from Latin, the language of origin for most French words. Spy, it turns out, comes from the French verb espier (“to spy”), itself from the Franconian spehôn, meaning “to observe attentively.” Franconian, known in French as francique, was a German dialect from a region that today includes Bavaria, known as Franconia. The French word was attested in the 11th century, and had come to Middle English by the 13th century.
A word’s etymology is its biography; sometimes it reveals a disguise. It seems fitting that the word spy is an English-looking monosyllable borrowed from French that ultimately comes from Germanic roots.