abettor

or a·bet·ter

[ uh-bet-er ]
/ əˈbɛt ər /

noun

a person who abets.

Origin of abettor

From the Anglo-French word abettour, dating back to 1505–15. See abet, -or2
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

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