Besides "A miserable little pile of secrets".
Now with the meme answer out of the way, what makes a male specimen of the species Homo sapiens a man, instead of the numerous other derogatory terms to describe those that for whatever (internal and/or external) reasons fails to meet the requirements to be a man? Following on, who decides what is a man (society in aggregate, women, other men, specific men (such as redpillers and MGTOW), or something else entirely)?
More specifically, is it based on a male human's actions? physical features? Place in the social hierarchy? Some combination of the above and others? What are the implications? (for example if man is defined as a male human who refuse to serve the greater social good does that mean civilization is inherently emasculating?).
As for why is this relevant to a subreddit all about gender dynamics? That's because a number of other popular topics rely heavily on what defines a man. Topics such as not all men/yes all men (the collective guilt, whether it applies to the gender in its entirety or just the visible sub segment). The problem of the beta provider, etc.
Oh, and one last thing. Yes the phrasing used is intentionally clunky due to people having a tendency to nitpick on small/minor details to make gotcha moments. Yes it's a lost cause but at least I'm making an autistic effort.