1. One who retards or delays.

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

• retirer,
• retaded,
• retardly,
• retalier,
• tarder,
• retaler,
• retaner,
• retarderd,
• reqarded,
• retared,
• rewarde,
• retardid,
• reaader,
• reatarded,
• revarded,
• reterver,
• rearder,
• retorded,
• Ragarder,
• Rewarder

The plural of the "Retarder" can be the "retarders".

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