Dumb questions are just fine, we all have to learn. I know I have ask my fair share of them.
But when someone has had a tech class license for a long time and is on the radio all the time using repeaters they should know what the term simplex is or at least have a some idea of the concept.
It's kind of like sticking your fingers into an powered amplifier when you have no idea what you are in for.
You might say that could lead to a higher education the hard way.