The general definition of book smart is someone who is intelligent and very well educated academically. However, the term is usually used to contrast and compare with another term known as "street smart".

The stereotype of a book smart person is someone who is upper-class and well educated but less knowledgeable when it comes to handling important situations faced in bad neighborhoods and lower-class city areas (a.k.a. the streets). However, the stereotype of a street smart person is someone who is intelligent and knows how to handle important situations in the streets but is not as well-educated academically.
The more extreme and negative stereotypes are that book smart people are naive, easily manipulated, and have bad judgment in bad situations, while street smart people are unintelligent and incapable of achieving a higher education.

Both stereotypes aren't always true and any semblance of them are only due to different lifestyles and experiences.
Josh: Are you sure me and Jason will get along? Jason is street smart and I'm book smart. We will probably be very different from each other.

Mike: Nah, don't worry. Jason may be street smart but he is also book smart. I'm sure you two will have a lot in common.
Being able to succeed scholastically, and not necessarily in the real world.
sure she's book smart, but she can't cook a potato!
by Malinda October 2, 2002
A term used by D-students to rationalize their academic failings.
I might be a sociology major with a 1.5 GPA, but that just means I'm not BOOK smart!
by CrunchyCookie November 22, 2010
A common characterization used by people who are uneducated to describe and feel superior to people who are, themselves, actually educated.
"Well, sure he's all book smart, but can he change an oil filter?"
by Lynns Daughter February 12, 2010
To excel with academia, and SUCK with real life.
A book smart professor was hit by a bus. Brilliant on paper, dull in life.
by cannedgoods October 18, 2005
A disparaging term coined by people who are hood rats to make themselves feel better because they are not as smart as people who are highly educated.
Hoodrat: You're so book smart, you're still stupid.

Educated Person: That really hurts coming from a drug dealer living out of an abandoned apartment.
by Daniel81 February 28, 2017
Academically inclined. Studiously clever.
He might be book smart, but every time you send him out to buy some smoke he gets bitch slapped by the dealer who palms him off with skanky brown horseshit.
by Dirtycash July 22, 2005