A form of hip-hop music that is socially conscious. Emphasis is placed upon the lyrics and beat production, usually inspired by the world around the producer/rapper. Few artists adopt the style for fear of being seen as nerdy, but it is far from that.
Common, Kanye West and Talib Kweli all make backpack rap.
A person who rides your back so hard you need to pry them off. Often a co-worker, teacher or manager in professional settings but could also be a significant other, semi-friend or admirer in social settings.
Rick was tagging along with us at the club last night. He just followed along behind me all night. I'm not taking him out anymore. He's such a backpack!
My boss just looms over my desk all day. He's constantly riding me. What a backpack!