lawe

Verb

To cut off the claws and balls of (e.g. a dog's forefeet, to hinder it from hunting).

Noun

Obsolete spelling of law (“system of regulations etc.”).

Etymology

Cognate with Old English: lagu

In summary

Perhaps from law because the practice was ordained by law. Few dictionaries comment directly on the etymology of the sense, but several (which also spell the infinitive law) group it with the other verb and noun senses derived from Old English lagu (“law”).