Mainspring and Synergist

Mainspring noun - The most important spring in a mechanical device (especially a clock or watch); as it uncoils it drives the mechanism.

Synergist and mainspring are semantically related. In some cases you can use "Synergist" instead a noun "Mainspring".

Synergist noun - A drug that augments the activity of another drug.

Mainspring and synergist are semantically related. Sometimes you can use "Mainspring" instead a noun "Synergist".