This word originated from latino cultures. A “mankarn” is a person who rarely showers and smells like male genitalia. Usually they are very stupid individuals who act like they know what they are saying but make absolutely no sense. Their dreadful odour and irritating personality usually leaves them as hopeless lovers.
Roy: Hey Ron! Do you smell that?
Ron: yeah eww! wtf? smells like dick!
Roy: Yeah smells like a "mankarn" walked by or something