Involuntary trouser defecation
From Love-shy.com wiki: A wiki for the dating-challenged
The plight of an involuntary celibate individual can be compared by analogy to that of one who has suffered involuntary trouser defecation. From a distance, the defecation sufferer will appear no different than any other individual, but nearby, the overwhelming odor will be obvious.
Involuntary trouser defecation is similar to involuntary celibacy in that from a distance, an incel will appear little different from the average person. But nearby, or when talking to the person, it becomes obvious that they are incel due to idiosyncratic behavioral characteristics, naivete regarding certain social norms, and dress sense. It can best be described as the "stink" of incel.