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2.
A mix of simplicity and complexity
Person 1: Whoa for some reason that shirt looks really simple and complex at the same time.

Person 2: Yeah I know. I wore it for that exact reason. It is simplex
by Ethan Sch January 06, 2008
 
1.
A term used in two-way radio communications meaning direct, radio-to-radio communication.
The repeater was down, so we switched to 146.52 simplex and continued to talk.
by Scout 740 Baker April 16, 2004
 
3.
as in the herpes simplex, a disease you gits from ho's

a large group of simple people.
that simplex, they all got the bus into town and wus so stupid they all got the herpes simplex and the crabs from the local hookers! Then they done given it to their wives! SHIT!
by Gwando November 09, 2003