Came across it used curiously in a Los Angeles Times blurb about the search for an AIDS vaccine:
AIDS Healthcare Foundation President Michael Weinstein says vaccine
research beggars known, effective treatments for HIV-positive people.
I had to stare at that for quite some time to realize beggars wasn't functioning as a noun.
Per American Heritage Dictionary (via dictionary.com):
beggar: tr. v.
1. To make a beggar of; impoverish. 2. To exceed the limits, resources, or capabilities of: beauty that beggars description.