The Grammarphobia Blog

Defused, diffused, and confused

Q: Once again, someone I consider a fairly good writer has “diffused” an explosive situation. I’m pretty sure it should be “defused.” Is there any leeway on this? Also, I pronounce the two verbs differently. Can they be pronounced the same?

A: “Defuse” and “diffuse” are unrelated and have no overlapping meanings, though they are widely confused. To “defuse” is to inactivate or render harmless. “Diffuse” is both a verb (meaning to spread out) and an adjective (meaning widespread).

The word that writers ought to use when they mean neutralize a volatile situation is “defuse,” a verb that developed during World War II and means literally to remove the fuse from a bomb.

The first published reference for “defuse” in the Oxford English Dictionary is from 1943: “A group of fliers defused a 1,000-pound bomb that had jammed in the racks when their plane was flying … over an Italian target.”

If ever a verb was a good candidate for figurative usage, this was one. Here’s a figurative example from 1958: “Thought has to be given now, without delay, to the means of reducing the risks involved in this inevitable act of disengagement – of defusing it, in effect.”

As you suspect, the word has no relation at all to “diffuse,” which entered the English language around 1400 as a now-obscure adjective meaning “confused, distracted, perplexed; indistinct, vague, obscure, doubtful, uncertain,” according to the OED.

The verb “diffuse,” meaning to pour out or spread widely, showed up in the late 1500s. It was derived from the Latin diffundere, to pour out or away.

In the early 1700s, according to the OED, the adjective came to mean “spread through or over a wide area; widespread, scattered, dispersed: the reverse of confined or concentrated.”

The pronunciations of “defuse” and “diffuse” do overlap somewhat, perhaps contributing to the confusion between the two words.

“Defuse” is pronounced dee-FYOOZ. But “diffuse” has two pronunciations. The verb is dih-FYOOZ and the adjective is dih-FYOOCE (the “i” in each sounds like the one in “pit”).

Let’s hope these two very different words don’t become fused!

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