A friend of mine was quite titillated today to discover that gruntled is a word meaning "satisfied", as opposed to the much more common word disgruntled. Gruntled has actually been around longer; the dis- wasn't affixed until the 1680s, and it really didn't become popular until the 1870s, when it utterly quashed gruntled into the realm of archaic terminology. Okay, so dis- is a Latin prefix meaning "lack of", and it comes from Proto-Indo-European dis-, "apart". -Le is just a frequentive suffix, so the root in fact derives from our word grunt, which, of course, refers to a snorting sound. In Middle English, this was grunten, in Old English, it was grunnettan, in Proto-Germanic it was grunnatjana and in PIE it was ghrun. Not much semantic change there, but at the end it meant something more like "shout". Beyond that, I'm guessing there's an onomatopoeic component. This etymology certainly gruntled me!
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.