Smart can have many definitions. But generally speaking smart people;

• question everything while seeing commonalities in everything.
• love to read and learn.
• see everything as being a math equation to be solved.
• are referred to as walking encyclopedias and can quickly recollect information they have already absorbed from years before.
• know that to retain it, you must maintain it, so journaling is a habit they adopt when they are young.
• are creative. Most are born with natural talents in art, music, etc.
• enjoy their alone time.
• can suffer from anxiety and addictions. ( Believe it or not, geniuses are not exempt from addictive behaviors..)
• understand that they don't know everything. Therefore, they crave to understand everything they possibly can while they are here.
• work best independently.
• are open-minded.
• admit when they are wrong or could be wrong.
• are honest to a fault.
• are mostly optimistic and driven to meet their goals, no matter the time and work involved.
• Can set their own pace.
• are argumentative and curious as children.
• are genuinely curious as adults which leads to awkward interactions with others.
• ask “why” a lot in their formative years.
• give excellent one-liners.
• are often misunderstood by the world around them.
• can suffer from imposter syndrome as both a child and adult.
• Their explanations are like lightbulbs going off in their heads and yours, too.
• are human, but some will seem of another world, place, or time.
• make you question your own life without even trying.
• are born this way for a reason that they aren't even sure of as to the why, but will always be in search of the answer for the rest of their lives.