fog

verb

fogged; fogging

transitive verb

1

: to cover, envelop, or suffuse with or as if with fog

fog the barns with pesticide

2

: to make obscure or confusing

accusations which fogged the real issues

3

: to make confused

4

: to produce fog on (something, such as a photographic film) during development

intransitive verb

1

: to become covered or thick with fog

2

a

: to become blurred by a covering of fog or mist

—often used with up

My glasses keep fogging up.

b

: to become indistinct through exposure to light or radiation

Synonyms of fog

• confuse
• cloud
• blur
• muddy
• obfuscate

Examples of fog in a Sentence

The steam from the pot was fogging the window near the stove.

The bathroom was all fogged up after my shower.

politicians who try to fog the issue instead of taking a stand

Recent Examples on the Web

If your windows fog up frequently, switching your AC from recirculate mode to fresh air mode can help equalize humidity levels. —Jessica Safavimehr, Southern Living, 28 May 2026

Steam from a hot shower does not just fog up the mirror. —Lauren Jarvis-Gibson, Fort Worth Star-Telegram, 30 Apr. 2026

After the usual avalanche of draft-week nonsense, and enough misinformation to fog up half the league, the noise gives way to the decisions. —Eddie Brown, San Diego Union-Tribune, 23 Apr. 2026

Then remove the spark plug and add a fogging oil or small quantity of Marvel Mystery oil to the cylinder and replace the spark plug. —John Paul Senior Manager Public Affairs and Traffic Safety Aaa Northeast, Hartford Courant, 17 Apr. 2026

Word History

First Known Use

circa 1592, in the meaning defined at transitive sense 1

Phrases Containing fog

• brain fog
• fog lamp
• fog light
• ice fog

Rhymes for fog

• blog
• bog
• clog
• cog
• dog
• flog
• frog
• grog
• hog
• jog
• log
• og

Kids Definition

fog

1 of 2 noun

ˈfȯg 

ˈfäg

1

a

: fine particles of water floating in the atmosphere near the ground

b

: a fine spray or a foam for firefighting

2

: a gloomy condition of the atmosphere or a substance causing it

3

: a state of mental confusion

spent the morning in a fog

fog

2 of 2 verb

fogged; fogging

1

: to cover or become covered with or as if with fog

2

: to make confused

Medical Definition

fog

transitive verb

ˈfäg, ˈfȯg 

fogged; fogging

: to blur (a visual field) with lenses that prevent a sharp focus in order to relax accommodation before testing vision