Meaning & use
fogging up
Last updated
“fogging up” is a form of “fog up”. See that entry for the full set of meanings.
Meanings
verbintransitive
Becoming covered with a thin layer of small water drops so that you cannot see through clearly.
Grammar: No object: glasses, windows and mirrors fog up by themselves. The full verb is 'fog up'; 'fogging up' is its -ing form.
Patterns
- something is fogging up
- start fogging up
My glasses keep fogging up when I wear a face mask.
The car windows are fogging up because it's cold outside.
The bathroom mirror is fogging up after your hot shower.
verbtransitive
Making a surface such as glass become covered with a misty layer so it is hard to see through.
Grammar: Takes an object: the steam or your breath fogs up the glass.
Patterns
- something fogs up something
- fog up the windshield
The steam from the kettle is fogging up the kitchen window.
Breathing on the cold glass is fogging up the lens of my camera.
Cooking without a fan is fogging up all the windows in the flat.
Word forms
| base form | fog up |
|---|---|
| third person singular | fogs up |
| past tense | fogged up |
| past participle | fogged up |
| -ing form | fogging up |
Common combinations
- glasses fog up
- My glasses fog up every time I come in from the cold.
- windows fog up
- The car windows fog up when five people get in.
- mirror fog up
- The bathroom mirror fogs up during a hot shower.
- fog up completely
- The windshield fogged up completely within a minute.
Synonyms and how they differ
- mist up
- Very similar and common in British English for glass and windows; 'fog up' is used in both British and American English.
- steam up
- Focuses on steam or heat as the cause, while 'fog up' can also be caused by cold air or breath.
- cloud
- Used mainly for liquids or mirrors becoming less clear; it is more literary and less common for glasses.
Opposites
Word family
Commonly confused: fogging up or fogging?
fogging up vs fogging
'Fogging' alone can mean spraying a room with chemicals to kill insects, so the full phrase 'fogging up' is clearer for misty glass.
Practice
My sunglasses keep ______ up when I go from the cold street into a warm shop.
Choose one answer.
After 'keep' we use the -ing form, so 'fogging up' is correct. 'Fogged up' would describe a finished state, and 'fog' or 'fogs' cannot follow 'keep' in this pattern.
Make it your own
Write a sentence using “fogging up”, then check it and compare it with the examples above.