The prefix paleo identifies something “ancient,” or “old.” Its association with pre-historic man gives it a knuckle-dragging caveman sensibility.
When defining the paleoconservative, Chilton Williamson, Jr wrote of something that was an “expression of rootedness: a sense of place and of history, a sense of self derived from forebears, kin, and culture—an identity that is both collective and personal.”
In a similar vein, I would define paleomasculinity as a collective and personal sense of manhood that is grounded in history and derived from forebears, kin, and culture. A pre-feminist understanding of what it means to be a man, and a conservative resistance to re-definition of manhood based temporary circumstances.
The (feminist) New Man believes that we are not men, but merely people. He believes that manhood is of marginal significance in the modern world, that gender roles are outdated and unnecessary. He believes that men and women should be treated equally, and that—reproductive plumbing and a few physical differences aside—men and women are basically the same.
The (anti-feminist) PaleoMan finds meaning and worth in historical masculine ideals. He believes that men and women are significantly different, and that society works better when men and women work together, filling different roles.
I will probably revise this definition or expand it as I develop it over time.