Slacken (verb)

1. To reduce the tightness of.
2. To become less active or intense.

Origin:

Middle english (in the sense "become lax or loose"): from the stem of old english slæcian, of germanic origin; related to dutch slakken and german schlacken.

Examples:

1. He slackened the rope and the boat began to drift.
2. The tension in the room slackened as they started to laugh.
3. He slackened the pace of his work as he grew tired.
4. As the day went on, the storm began to slacken.
5. He slackened his grip on the steering wheel and relaxed.