The most common and most likely answer to this crossword clue is the 6 letter word HELPER
H
E
L
P
E
R
Buddy explains!

The straight part
We know that "abettor" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case abettor = helper.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does HELPER mean?
HELPER noun- One who helps; an aide.
- That which helps; anything serving to assist.
- A person who does cleaning and cooking in a family home, or in a market; domestic employee.
- A locomotive that assists a train, usually on steep gradients.