Incel, as in a cell in Excel?
Involuntary Celibate. Guys who can't get laid and aren't happy about it.
Depending on how you look at it, they're either losers worthy of mockery or the predictable result of a larger social shift that has devalued and emasculated men, leaving them angry and confused about their place in society.
Lots of press lately about "Incels" including an article I posted the other day from a lefty demanding speech codes to combat their message.