fog 1 
(fôg, fŏg)
(fôg, fŏg)n.
1. Condensed water vapor in cloudlike masses lying close to the ground and limiting visibility.
2.
a. An obscuring haze, as of atmospheric dust or smoke.
b. A mist or film clouding a surface, as of a window, lens, or mirror.
3. A cloud of vaporized liquid, especially a chemical spray used in fighting fires.
4.
a. A state of mental vagueness or bewilderment.
b. Something that obscures or conceals; a haze: shrouded their actions in a fog of disinformation.
5. A blur on a developed photographic image.
v. fogged, fog·ging, fogs
v.tr.
1. To cover or envelop with fog.
2. To cause to be obscured; cloud.
3. To make vague, hazy, or confused: a memory that had been fogged by time.
4. To obscure or dim (a photographic image).
v.intr.
1. To be covered with fog.
2. To be blurred, clouded, or obscured: My glasses fogged in the warm air.
3. To be dimmed or obscured. Used of a photographic image.
[Perhaps of Scandinavian origin.]
fogger n.