tcyandy
What are you studying that has made you ask this question?
If you are studying for the JAA/EASA ATPL then the answer they are looking for is.
Propeller torque is resisting the rotation of the propeller. Engine torque is generating the rotation of the propeller. If the propeller is at a constant RPM then these are equal and opposite.
If you are studying something more technical then some of the other posts in this thread are more relevant.