An individual who is likely to fail to exercise the care expected of a reasonably prudent person in like circumstances.
Chronically careless.
Do not use him as a reference, he is negligentable.
A belief system that supports the act of going out of your way to not know things, to be negligent is sometimes a way to keep ones confidence, mental stability, or even schedule, in tact, purposeful ignorance.
Winston: Don't you want to know what's going on?
Schamous: Sure but if I remain NEGLIGENTIC, I'm not dumping my time and energy into something that might be out of anyone's control and prolonging any self induced suffering.