This is a tough question to answer and just my experience. In the sports venue, I do identify a man physically first, in the locker room shower or dressing room I observe all of him-his face right down to his feet. Most often I hear him speak with other men, the voice-the character of the voice, the content is muted. I watch him move about, get ready for whatever.
On occasion in the gym I talk to him observe his reaction to me: his words his body language.
Things I experience, a good meaningful handshake, a hearty masculine laugh, a balanced physique, an amazing move or feat in sport, a well spoken, soft spoken man. A stare and smile that would make my heart rate jump.
I don't attach an age, a culture, a political slant, a religious slant, a sexual preference . I don't expect him to prove his manhood on the spot. He takes great satisfaction in being a man.
Assertive, reliable to self and others, respectful, desire to succeed, a good role-model, at times a hero.