Haziness is a quality of being foggy, cloudy, or out of focus. The haziness at sea today means that it will be difficult for you to navigate your sailboat.
There's weather-related haziness, which is caused by water particles or dust and smoke, like the haziness you see in Los Angeles on hot days. There's also a figurative type of haziness that relates to anything vague or undefined: "The haziness of my memory makes me unsure if this happened in 2008 or 2009." The noun haziness stems from hazy, which we know has a nautical origin but is otherwise a mystery.