A term often used in the criticism of music, films, television, games, etc, meaning lacking sensitivity or the capacity for deep feeling. It's often used in a context wherein the user does not like the item in question but otherwise lacks any more specific or valid criticism to level against it. It's also sometimes used to dismiss entire genres that the user is unfamiliar with or bigoted against.
"Electronic music is so soulless."
"Here we go again, another soulless rehash of ______."