Adjective - An individual's relationship state in which they are single but would like to sow their oats with no strings attached.
Etymology - Married individuals that commit adultery have a mentality that it's ok because there's no commitment involved. Combining the adulterous mentality of the word married, the end goal of staying single and embracing the word play of the word 'to mingle'.
Lisa: "So, do you have a girlfriend?"
John: "Nah, i've been mingle for several months now"