A radio code used by some urban public safety agencies as a professional sounding abbreviation for coffee, milk, no sugar. Intended to make a coffee run sound official and important.
"East 2, return to quarters. Make a stop on the way, 3 MNS."
Not knowing what you are supposed to do. This happens in what is obvious situations.
I was talking to this chick in the bar and she wanted to have a one night stand, but then I pulled a MNS and ended up on the just a friend list
To completely fail (brick) at something considered to be a basic skill - usually involving socializing of some sort.
I had an opportunity to score with two hot chicks tonight until I completely MNS'd it and wound up in the friend zone.