A. author
B. slaughter-house
C. encourager
D. factor
Explanation:
The word abettor means a person who helps, encourages, or supports someone in doing something (often something wrong or illegal).
In simple words: someone who assists or supports another person’s action.
So, the synonym of abettor is encourager.
Real-Life Example
- He was an abettor in the crime.
- He was an encourager or supporter of the crime.
One who supports action = Abettor