Word Usage – Is ‘Psithurism’ Really Used in English?

This is most likely a case of dictionaries having not caught up with an industry's lingo or jargon. Here are a few examples of using refactor:

You can also refactor other things besides formal expression languages. Like DocumentRefactoring. I refactored this definition several times in order to group similar ideas into their related paragraphs. Of course, I call that reorganization. It's all similar (except where it's different). (source)

Refactor mercilessly to keep the design simple as you go and to avoid needless clutter and complexity. (source)

For example, if a programmer wants to add new functionality to a program, he may decide to refactor the program first to simplify the addition of new functionality in order to prevent software entropy. (source)

These examples were found with ten minutes of searching.

In addition to the above, my own personal experience around programmers suggests that every single programmer who knows what refactoring is will understand what refactor means. Furthermore, Visual Studio's refactoring menu actually calls it refactor:

I don't have comparable information for the Oxford English Dictionary—but historically, Merriam-Webster has not been terribly welcoming to giggles, gurgles, grunts, and other onomatopoeic ejaculations. The tendency goes back to Noah Webster himself, who included entries for "ha" and "hey" in his Compendious Dictionary of the English Language (1806), but not for "hah," "ha-ha," "hi," or "ho," though "hah" goes at least as far back as the play Sir Gyles Goosecappe Knight (1606), and though the Eleventh Collegiate Dictionary (2003) dates "ha-ha" to "before 12c," "hi" to "15c," and "ho" to "15c." (Johnson's 1756 Dictionary has entries for "ha," "hey," and "ho," but not for the others.)

In the United States, "hah" and "ho" debut in Webster's 1828 Dictionary of the English Language, which also acknowledges (under the entry for "ha") that "When repeated, ha, ha, it is an expression of laughter, or sometimes it is equivalent to 'Well! it is so.'" Nevertheless, "ha-ha" in the sense of laughter doesn't receive its own entry in Merriam-Webster's until the Seventh Collegiate Dictionary (1963), which also marks the Collegiate series debut of "hi."

For additional context, consider the Merriam-Webster's handling of "er," "heh," "huh," "huh-uh," "nuh-uh," "ugh," "uh," "uh-huh," "uh-oh," and "uh-uh." The Eleventh Collegiate provides first occurrence dates for six of the words, but the first appearance of each in a Collegiate series dictionary is typically much later:

• "huh," dated to 1608, debuts in the Ninth Collegiate (1983)

• "ugh," dated to 1678, debuts in the First Collegiate (1898); it doesn't appear in the Webster's Academic Dictionary of 1895

• "er," dated to 1862, debuts in the Eleventh Collegiate (2003)

• "uh-huh," dated to 1889, debuts in the Eighth Collegiate (1973)

• "uh-uh," dated to 1924, debuts in the Tenth Collegiate (1993)

• "uh-oh," dated to 1971, debuts in the Tenth Collegiate (1993)

• "heh," "hmm," "huh-uh," "nuh-uh," and "uh" do not yet appear in the Collegiate series

Based on these instances, I wouldn't expect Merriam-Webster's to start taking "kekeke" seriously as a word in standard English before the year 2035 at the earliest, even assuming that it were to quickly achieve the popularity of "uh-oh" (which seems unlikely).