I'm going to use a member of my wife's family as an illustration.
This gentleman owns a window cleaning business. He's a successful man with dozens of employees. --Lives in a nice house and drives a nice car. He's a JW elder and from what I can see, is highly regarded in his congregation.
This man is not stupid by any stretch of the imagination. He's way above average in intelligence.
What this gentleman is missing is depth:
He regards himself as knowledgeable when it comes to the Bible, but doesn't understand the difference between the JW's wild allegorical interpretation of it and actual scholarship. He mistakes the former for the latter.
He can't compose a simple sentence in Ancient Greek, or for that matter, even pronounce the word Koine, and yet believes he's very conversant in Bible translation. He doesn't understand what higher criticism is or why it is necessary, but holds a very dim view of it.
This gentleman has no children of his own, is not qualified as a grief counselor and his ideas of marriage are skewed by the belief that men are inherently more intelligent than women. And yet he gives advice in all these areas.
This gentleman knows very little about human physiology and nothing about medicine and yet as a JW elder believes he is knowledgeable in a very esoteric branch of emergency medicine. --Much more so than medical professionals.
In short, he's an alumni of Window Washer Uni.
I know the term gets used thoughtlessly sometimes, but there are legitimate examples of what it's meant to describe.