Douglas Harper's Etymology Dictionary
Wiktionary
a. contrary to intuition or common sense.
WordNet
adj. contrary to what common sense would suggest
Wikipedia
A counterintuitive proposition is one that does not seem likely to be true when assessed using intuition, common sense, or gut feelings.
Scientifically discovered, objective truths are often called counterintuitive when intuition, emotions, and other cognitive processes outside of deductive rationality interpret them to be wrong. However, the subjective nature of intuition limits the objectivity of what to call counterintuitive because what is counter-intuitive for one may be intuitive for another. This might occur in instances where intuition changes with knowledge. For instance, many aspects of quantum mechanics or general relativity may sound counterintuitive to a layman, while they may be intuitive to a particle physicist. Nevertheless, counter-intuitive concepts are psychologically more preferred than intuitive concepts like in Von Restorff effect.
Flawed intuitive understanding of a problem may lead to counter-productive behavior with undesirable outcomes. In some such cases, counterintuitive policies may then produce a more desirable outcome. This can lead to conflicts between those who hold deontological and consequentialist ethical perspectives on those issues.
Usage examples of "counterintuitive".
In fact, the truth is frequently the opposite of what it seems, and the counterintuitive path is often the right one.
Sometimes this can mean taking actions that might be described as counterintuitive, though few of us will be called upon to wade into the ocean.
To be sure, this is a counterintuitive way of thinking, at least at the outset.
It is at least counterintuitive to say that it is more patriotic to attack America than to defend it.
Bryson lashed out with his left arm, like a cobra, directly toward the blade--a counterintuitive move, because it meant rising up and greeting the instrument of death, or the appendage that held it, rather than retreating from it--and as he seized the wrist of the hand holding the stiletto, the harridan was clearly taken by surprise.
If we really are to be open to counterintuitive ideas in physics or social organization or anything else, we must grasp those ideas.
Modern economic signal theory has cast advertising in a new and surprising - though by no means counterintuitive - light.
You told me the best way to hide is to stick out, because it runs counterintuitive to human nature.
The military navigational gear which Oblo had liberated had counterintuitive properties which Sirkin would learn best by experience.
The idea that Jupiter orbit was somewhere you could go was as profoundly counterintuitive as the Internet to a baby boomer.