To uninstall tnefDD do the following:

Drag tnefDD.app from the Applications folder to the Trash
Drag tnefDD.app from the Applications folder (or wherever else you put it originally) to the Trash
There is only one step required to uninstall tnefDD.
Drag tnefDD.app from the Applications folder to the Trash
Drag tnefDD.app from the Applications folder (or wherever else you put it originally) to the Trash
Once you have dragged tnefDD to the Trash, it is uninstalled.