Downswing and Drop-off

Downswing noun - A swing downward of a golf club.

Drop-off and downswing are semantically related in decline topic. In some cases you can use "Drop-off" instead a noun "Downswing", when it comes to topics like increase.

Drop-off noun - The amount by which something is lessened.

Downswing and drop-off are semantically related in position topic. You can use "Downswing" instead a noun phrase "Drop-off", if it concerns topics such as decline, increase, fall.