Word Choice: Viscous vs. Vicious

‘Viscous’ and ‘vicious’ are both adjectives. They’re also close enough in spelling that it’s easy to get them mixed up when they’re written down. But these terms have very different meanings, so check out our guide below to find out how they should be used.

Viscous (Thick and Sticky)

We use ‘viscous’ to describe something thick and sticky. For instance:

The mixture was too viscous to stir.

Honey is a viscous substance produced by bees.

A ‘viscous’ liquid typically doesn’t flow smoothly.

You can see this for yourself if you look at how quickly honey or treacle flows down an incline compared to water. The thickness of a liquid is known as its ‘viscosity’ (e.g. water has low viscosity compared to honey).

Vicious (Violent or Cruel)

Most of the time, ‘vicious’ means ‘violent’, ‘fierce’ or ‘cruel’. For example:

The vicious dog snarled when it saw the cat.

They began a vicious assault on the enemy fort.

Sometimes, however, we can use ‘vicious’ to mean ‘painful’ or ‘intense’:

I’ve had a vicious headache all day.

Even here, though, ‘vicious’ implies that something is harmful or negative.

We see this negativity again in the phrase ‘vicious circle’.

This is a process where two problems cause or reinforce one another, making it difficult to escape or solve either one.

For example, imagine you have a toothache but you are scared to go to the dentist. Putting off going may make the condition worse, requiring a more painful treatment, which could make going to the dentist even more scary, etc. This cycle makes each problem worse, so it is a ‘vicious’ circle.

Summary: Viscous or Vicious?

Although these terms look similar written down, they differ in meaning:

• Something is viscous if it is thick and sticky, like honey or treacle.
• To be vicious is to be cruel, violent or aggressive.

Be wary of spellcheckers with these terms, too. If you type ‘vicous’ by accident, for example, Microsoft Word will suggest both ‘viscous’ and ‘vicious’ as corrections, so you need to pick the right one! To make sure your writing is error free, though, you can always ask a proofreader.