Slugabed \SLUHG-uh-bed\ , noun;
1. One who stays in bed until a late hour; a sluggard
I'm pretty sure this word was made up by someone's mom and put here as a joke. Slugabed?
It does appear in the Oxford English Dictionary, and the etymology is exactly what you'd think: slug- + abed ("lazy" + "in bed") = slugabed. Surprisingly (well, maybe not when you consider that the component words are somewhat archaic) the word dates back to at least 1592 when Shakespeare wrote in Romeo & Juliet IV.V.2 'Why Lambe, why Lady, fie you sluggabed.'
I'm going to hazard a guess here, based on the Shakespeare line, that this word was actually in English slang long before 1592. The trouble with etymology dictionaries and historical linguistics is that spoken language is incredibly rich and vibrant, but also fluid and variable. The goal of historical linguistics is to re-create what a language looked like at various points in time and to trace its evolution. If you were to read Beowulf in its original form it would be nearly impossible (unless you've studied Old English extensively, in which case, good for you!), but that language was the basis of the English we speak today. The attempt to trace language and re-create it is very romantic and most people would probably find it interesting, but it's an enormous task that is basically impossible. The problem is that language disappears as soon as it's used. In the absence of recording technology the things we say today are only recorded in the memory of those who heard them - but human memory is very fallible and people have a tendency to die. So, to trace words in the distant past we have to rely on written texts alone. Since literacy for the masses was not particularly common until recent centuries, most writing was done by specialists and scholars only. Imagine reading your psychology 101 textbook and treating it as a representation of English today, not an accurate picture. Shakespeare was a revolutionary playwright who wrote for the masses, not haute society. He used slang, vulgar speech, vernacular, and all sorts of 'improper' English that most writers of his generation would never dream of using in their compositions. Because of this, several words in the OED owe their first attribution to him. Keep in mind, he was not creating words that ended up 'sticking' simply because he wrote them (Lewis Carroll did do that, but that's another post), he was just reflecting the common language as he saw it.
*Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Sunday, October 24