When people think of intelligence they usually think first and foremost of knowledge, with the implication being that someone who possesses knowledge is deemed intelligent and someone who lacks it is deemed to lack intelligence. These judgements are misguided and misconstrue what intelligence actually is defined as. Intelligence is the means or the methods that someone uses to solve problems. A person's intelligence isn't measured by what they know but rather by their ability to deal with the things they know nothing about when they are confronted with them. To that end, many people are a lot more intelligent than they give themselves credit for, and perceive many others of being a lot more intelligent than they actually are, simply because they appear knowledgeable.
To know that a carburettor supplies an ignition to an engine, or that a compiler takes human readable code and transforms it into machine readable binary, or that the vagus nerve is the primary component of the nervous system that triggers immune responses, or to be able to name every member of the Kardashian family is not an indicator or intelligence or lack thereof. These all represent subsets of knowledge that a person may or may not acquire and in most cases whether a person possesses these sets of knowledge depends on whether they have use for them in their everyday lives.