On another forum I frequent an Australian said, "Perhaps this is a way of nobbling the competition." What did he mean?

sabotage

It's a interesting word that I haven't heard. The online MW says that its etymology is perhaps an "irregular frequentative" of nab. Of course, I haven't heard of "irregular frequentative," either, so I don't know what that means.

It's apparently a chiefly British slang to mean "to win over to one's side" or "to incapacitate (a racehorse) especially by drugging."

Did it come from people who "nabbed" racehorses?