[…] the hot pavement by the playing field where the trees crisp together.

to loosen a knot; to loosen one's grip / hold on something

Where the original is close no version can reach it in the same compass.

The pea-coated gent at that word made a start, / And looked nervously round at the goods of our mart: “A vest, coat, and trousers, as soon as they’re done, I want, s’il vous plait, Messieurs Moses and Son.