Then again you could always go to the font of all wisdom on the interwebs - Wikiedia:
"Moxie originated as a patent medicine called "Moxie Nerve Food,"[1] which was created around 1876 by Dr. Augustin Thompson. Thompson claimed that it contained an extract from a rare, unnamed South American plant, which had supposedly been discovered by a friend of his, Lieutenant Moxie,[1] who had used it as a panacea. Moxie, he claimed, was especially effective against "paralysis, softening of the brain, nervousness, and insomnia."[1]
After a few years, Thompson added soda water to the formula and changed the product's name to "Beverage Moxie Nerve Food." By 1884 he was selling Moxie both in bottles and in bulk as a soda fountain syrup. He marketed it as "a delicious blend of bitter and sweet, a drink to satisfy everyone's taste."[2]
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Through extensive advertising, the neologism "moxie" has entered popular American usage with the meaning "courage, daring, and energy,"[9][10] as in "This guy's got moxie!"
Moxie is closely associated with the state of Maine. Its creator, Dr. Augustin Thompson, was born in Union, Maine. Moxie was designated the official soft drink of Maine on May 10, 2005.[11]"
Source:
http://en.wikipedia.org/wiki/Moxie