To have a life that is difficult, where the elements of the world seem to be against you all the time.
For example, life on the streets, the life of a hustler or a dealer.

actually the song is originally from annie. it's harder to be a red headed orphan then a gangsta.

Life itself; knowledge (and wisdom) gained by working for it, and not necessarily from a book.

The practical experience of life, including hardship and disappointments.

Often used by those who couldn't/didn't go to college for whatever reason and instead went through hardships and disappointments.

1a. Descriptive of the many violent, scary and/or emotionally difficult events that give young people their "smarts" and teach them about the daily struggle to survive in the streets.

1b. Something that an ignorant fuckwit who wouldn't know what to do with a book even if he/she owned one says when he/she finds out that you went further in education than him/her.

Someone who lives a life full of hardships.

1. A Unestablished yet active education system located worldwide with only One class: Street Smarts 101 in wich you learn from your enviroment & the costly mistakes you make

2. Street Education of the obvious or Street Common Sense