Macho is a very slippery thing. You don't read about it,

Macho is a very slippery thing. You don't read about it,
you don't write about it, you don't even know the
correct spelling of the word. In a vain attempt to keep
some semblance of masculinity, I didn't research the
roots of the word while writing this article, but I
can only assume that "macho" comes from "machismo,"
which sounds a hell of a lot like machine. Being macho
implies a tough, hard, blocklike approach full of
pistons and rods and axles and other big steel-type stuff.
-- Denis Leary from "Are you Man enough?"