Laudator Temporis Acti

J.A. Pitt-Rivers (1919-2001), The People of the Sierra (New York: Criterion Books, 1954), pp. 89-90:

The quintessence of manliness is fearlessness, readiness to defend one's own pride and that of one's family. It is ascribed directly to a physical origin and the idiom in which it is expressed is frankly physiological. To be manly is to have cojones (testicles), and the farmyard furnishes its testimony in support of the theory. Castrated animals are manso (tame), a castrated ox is not dangerous like a bull. A castrated dog, it is thought, will always run away from an uncastrated one. A man who fails to show fearlessness is lacking in manliness and, by analogy, castrated or manso. While it is not supposed that he is literally devoid of the male physiological attributes, he is, figuratively, so. That part of his person does not possess the moral qualifies properly associated with it.

Id., p. 91:

The word which serves literally to translate manliness (hombría) also contributes to the same conception:

"The modern race is degenerate," said a friend once, "in the days of our grandfathers there was more manliness than today." To be "muy hombre" is to have an abundance of that moral quality which we have been discussing, and, through it, to command the respect of one's fellows.