From here it is not very far to “greenhorn” meaning a new immigrant from a foreign country, although the word had to take one more intermediate step before this happened –- namely, to be applied to rural bumpkins moving to the city. A mid-18th-century Englishman arriving in London from the country wrote, for example, that “A slouch in my gait, a long lank head of hair and an unfashionable suit of drab-coloured cloth… denominated me a greenhorn,” and in New York City, too, the word first referred to hayseeds from out of town. As late as the year 1900, in fact, Greenough and Kittredge’s popular Words and Their Ways defined a greenhorn as “one who knows nothing of city life.”
In answer to Weiss’s question then, “greenhorn,” which by the early 20th century in America had largely come to mean a new immigrant from Europe, was not just a term for Jewish immigrants. What may in part have owed its currency to Jewish influence was the alternative form of “greener,” from the Yiddish griner, itself an adaptation of “greenhorn”; yet “greener,” too, in the sense of a country boy in the city, is attested to in American English as early as 1875, before the large-scale Yiddish-speaking immigration to America. commenced. The form “greeny” or “greenie” was also widespread in America and continued to be used for country hicks long after “greenhorn” had lost that meaning.
Jews who once were griners themselves had no compunctions about laughing at newer ones. Soon after arriving in New York, Motl tells us, his older brother Elye and Elye’s friend Pinye argue why the first meal of the day is called in English “brekfish.” And Motl relates:
Elye said it’s called brekfish because you eat herring. “In that case,” said Pinye, “why isn’t it called brekherrink?” “What a dope you are!” Elye said. “Don’t you know a herrink is a fish?” Pinye saw that Elye had him there and said: “You know what? Let’s ask an American.”