Games on steam that have been abandoned by their developers, left to die in (usually) an unfinished state. These games clutter the steam store but steam refuses to remove them as they make money still. Some players cling to the game despite its abandonment, and in some cases, people don't know or care that it is abandoned. Most of the time these kinds of games can be considered a ripoff as they are sold for a high price for a buggy mess of a unfinished product. Some of these games break as they age and become unplayable. Games that are endorsed by the development team though are not being actively updated do not count as abandonware, as the developers and the community still regularly upkeep and/or endorse the game.
I have so many Steam Abandonware games