Definition from Wiktionary, the free dictionary
abettor (plural abettors)
- One that abets an offender; one that incites; instigates; encourages. [First attested from 1350 to 1470.]
- A supporter or advocate. [Late 16th century.]
- Abettor is usually used in a legal sense.
- abettor, accessory, accomplice. These words denote different degrees of complicity in some deed or crime.
- An abettor is one who incites or encourages to the act, without sharing in its performance.
- An accessory supposes a principal offender. One who is neither the chief actor in an offense, nor present at its performance, but accedes to or becomes involved in its guilt, either by some previous or subsequent act, as of instigating, encouraging, aiding, or concealing, etc., is an accessory.
- An accomplice is one who participates in the commission of an offense, whether as principal or accessory. Thus in treason, there are no abettors or accessories, but all are held to be principals or accomplices.
- (supporter): Nowadays it usually refers to a reprehensible act that is supported.
- Lesley Brown (editor), The Shorter Oxford English Dictionary, 5th edition (Oxford University Press, 2003 , ISBN 978-0-19-860575-7), page 4