In other words it means genius, however, this is a new breed of genius. It is defined as someone who is part retarded and parted genius,"Like rain man". To be a jengus you must show strong qualities of excelled genius, at the same time showing qualities of intellectual ihabition.
"Your son displays very jengus qualities"
"like a jengus, granpa displays patterns of alzheimer's"
"Roger Christian's direction in Battle Feild Earth displayed very jengus qualities"