It stands for “involuntary celibate.” I’m not sure I agree that it started out “innocent,” though. I’ve yet to meet someone who identified as an incel that didn’t at least partially blame women for the situation they were in.
I heard about it early on and actually went to visit the sub out of curiosity when it was still somewhat innocent. There were definitely misogynistic posts there already, but plenty of innocent ones as well that didn’t blame women for the outcome. I remember later on there was even a post made by one of the mods about how he was retiring from the sub, because it had been taken over by the misogynists and no longer served the purpose it was intended to. I would bet you have met men that qualify under the original definition, but who don’t identify with the label now because of what it’s come to be associated with.
Just like how r/fph wasn’t originally about hating on obese but really pointing out the flaws in logic they use to justify over eating. But we all know what it turned to which got it banned. I’m not sure it was ever as bad as the admins claimed…I think it was more to set an example.