A lot of people assume that the “phase” spelling covers everything. It might not have fazed you, but it’s fazed a lot of editors over time.
Remember:
- “Phase” is either a verb, meaning to carry out systematically (i.e., “phase in” or “phase out”), or a noun, meaning a stage (e.g., the phases of the moon).
- “Faze” is a verb meaning to disturb or embarrass. It commonly appears in its negative form, “unfazed.”
Interestingly, the word “faze” is a 19th-century American invention, stemming from the word “feeze,” which meant to drive away or to frighten. Here we have another tale of a word that has been all but forgotten, but in this case, the slang variant born out of the American Wild West—”faze”—is still going strong. I don’t know the cowboy or cowgirl who started it all, but it’s surely an ace-high grammarian tale.