[orangethirty]

The difference is quite makred. A conventional marketer focuses on using, well, conventional methods. They use already made marketing tools to get their messages across. Seldom do they dare innovate in any regard. They basically apply the same thing to every idea.

A growth hacker:

    builds his/her own tools (including software)
    is always developing new marketing tools 
    works to combine conventional with new

Its not a new term, but has been getting some attention in the past years.