The most common and most likely answer to this crossword clue is the 4 letter word ABET
I've seen this crossword clue in Financial Times
A
B
E
T
More clues leading to the result ABET
- Bishop in drink coming over? Help!
- Assist in a B movie?
- Help Nancy and Jack first
- Support Lincoln Town at the outset
- Crookedly endorse last thirteen letters?
- Assist with a B movie?
- Are accessories to answer wager?
- Encourage wrongdoing in Lincoln Weather Centre
- Sinfully help gambler regularly getting tense
- Aid president’s given to Turkish leader
Buddy explains!

The straight part
We know that "Aid" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case aid = abet.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 ABET mean?
ABET noun- Fraud or cunning.
- An act of abetting; of helping; of giving aid.
- To urge on, stimulate (a person to do) something desirable.
- To incite; to assist or encourage by aid or countenance in crime.
- To support, countenance, maintain, uphold, or aid (any good cause, opinion, or action); to maintain.
- To back up one's forecast of a doubtful issue, by staking money, etc., to bet.