• 2-minute read
• 11th March 2015

Word Choice: Defuse vs. Diffuse

Even if you have a good level of English, it’s still easy to use the wrong word by mistake. The most likely culprits are words which sound or look quite similar, which make it crucial to check your work thoroughly before submitting. Today, we explain the difference between the words “diffuse” and “defuse.”

Defuse (Disarm or Reduce Tension)

The literal meaning of “defuse” is to remove the fuse from something to disarm it, usually a bomb:

After receiving a call about a suspicious package, the police moved in to defuse the device.

We also use “defuse” metaphorically to describe reducing tension or anger to calm something or someone down:

Dan was getting really angry, but Jane defused the situation.

In this sense, we always speak about defusing a situation, never a person.

Diffuse (Spread Out)

“Diffuse” is most commonly used to mean “spread out” or “scatter.” This can be either as a verb, describing the action of scattering something:

The photographer used a special filter to diffuse the light.

Or it can be used as an adjective to describe something that has been scattered. Light can be diffused with a filter, for instance:

Diffuse light is often used in portrait photography, since it produces fewer shadows.

However, “diffuse” has a similar but more specific meaning in science, where it relates to the process of “diffusion”:

As the dye diffused through the solution, the movement of the particles became clear.

It is also possible to use “diffuse” in relation to speech or writing, where it means “lengthy” or “wordy” and often has a negative connotation of being boring:

The CEO’s speech at the awards ceremony was particularly diffuse. Several people fell asleep.

Defuse or Diffuse?

As you can see, these terms have very different meanings, so you should try to avoid confusing them in your written work. Thankfully, once you know their definitions, the differences make it easy to tell these words apart. Remember:

Defuse = Disarm a bomb/ease a tense situation

Diffuse = Spread out/overly long and wordy