You can unlock after reaching the fifth (green) area.
Clobots are clones that have been turned into enemies. They look like the normal clones but they carry a white sword and have one red eye.
To earn the achievement you have to jack one with the Jack Boy. So just sneak up behind one and jack away.
The first opportunity is at the start of the fifth area. You travel a few rooms right towards the flashing marker on the map and you lower a lift/elevator in a dark room. The Clobot will ride down on the lift.