Shortly explained: What is hedging?
In its essence “hedging” refers to securing a portfolio against risks. To do so you invest in the derivatives market in products (eg. futures) that counteract the risks you want to avoid (e.g. interest risks or currency risks)
What is trading?
A trader speculates on market development (eg. price increase of a specific stock) by using derivatives (e.g. call futures on that stock). Usually, the trader doesn’t hold a (spot market) portfolio that needs to be hedged. He just buys/issues the respective derivates.