1. Co-operation.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• nergy,
• synery,
• syngery,
• syney,
• synergys,
• eenergy,
• syergy,
• sinergy,
• synergie,
• senergy,
• senery,
• surergy,
• cynergy,
• inergy,
• ennergy,
• sergy,
• synergery,
• syenergy,
• asynerga,
• asynergi

• syneresis,
• synergist,
• synergism,
• synergetic,
• synercus.

The adjective form of the word "synergy" is "synergistic".

The plural of the "synergy" can be the "synergies".

The singular of the "synergy" can be the "synergy".