Stands for Old Man Sex Appeal.
1. An older man who has high sexual attraction.
2. Its a gauge women measure in their own mind when considering sleeping with and or admiring the sexual attractiveness an older man. Usually this gauge which is called the OMSA Meter is blindly boosted by how much money, power or fame this older man has. Do not mistake this for a sugar daddy as a poor older man can possibly have high OMSA.
For an older man to qualify for OMSA the woman who is measuring it with her OMSA meter has to be at least 10 years older than her.
Women that have unusual low standards of giving any man OMSA on their OMSA meter usually have daddy issues.
Girl 1: "I'm thinking of going out with a date with my boss at work. He's older than me."
Girl 2: "Does he have OMSA?"
Girl 1: "Yep sure does. He is on Johnny Depps level"
Girl: "Girl what the hell are you doing fooling around with that old fool, is your OMSA meter working properly?"