Become slower and Retard

Retard and become slower are semantically related in slow topic. In some cases you can use "Retard" instead a verb phrase "Become slower", when it comes to topics like slow down.

Retard verb - To cause to move or proceed at a less rapid pace.

Become slower and retard are semantically related in slow topic. You can use "Become slower" instead a verb "Retard", if it concerns topics such as slow down.