An alpha male is a man who takes charge, one who imposes his will on others, not the other way round. Other men want to be him, women want to be with him. An alpha male intimidates, hes unquestionably in charge, no matter what the situation. An alpha male is loud, brash, doesnt care what anybody else thinks.

What defines a sigma male?

Sigma male is a slang term used in masculinist subcultures for a popular, successful, but highly independent and self-reliant man. Another term for a sigma male is a lone wolf.

Whats an Omega male?

noun [countable] a man who chooses not to have a powerful or important role in a social or professional situation. While the alpha male wants to dominate and the beta male just wants to get by, the omega male has either opted out or, if he used to try, given up.