I got it from yourdictionary.com (the first link that came up when I googled it).  This is what Merriam-Webster has:
	Quote:
	
	
		| Main Entry: gad·a·rene Pronunciation: \ˈga-də-ˌrēn\
 Function: adjective
 Usage: often capitalized
 Etymology: from the demon-possessed Gadarene swine in Matthew 8:28 that rushed into the sea
 Date: 1922
 
 : headlong, precipitate <a gadarene rush to the cities>
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