n. The man who is least likely to take on a dominant role in a social or professional situation.
2011
These "omega male" partners of "breadwinner wives" are exactly the people who are transforming the gender dynamics of family and spurring a revolution in engaged fatherhood. In fact, the much-maligned qualities that qualify men as "omega males" — an apparent absence of testosterone, a childlike affinity for fun, a surplus of disposable time — are exactly the qualities that can transform men into remarkable fathers.
2010
American pop culture keeps producing endless variations on the omega male, who ranks even below the beta in the wolf pack. This often-unemployed, romantically challenged loser can show up as a perpetual adolescent (in Judd Apatow’s Knocked Up or The 40-Year-Old Virgin), or a charmless misanthrope (in Noah Baumbach’s Greenberg), or a happy couch potato (in a Bud Light commercial). He can be sweet, bitter, nostalgic, or cynical, but he cannot figure out how to be a man.
1992 (earliest)
[A]nthropologists have recurrently documented the existence of societies of hunter-gatherers in which there are neither alpha nor omega males.