The most common and most likely answer to this crossword clue is the 4 letter word BILK
B
I
L
K
Buddy explains!

The straight part
We know that "cheat" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cheat = bilk.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 BILK mean?
BILK noun- The spoiling of someone's score in the crib.
- A deception, a hoax.
- A cheat or swindler.
- To spoil the score of (someone) in cribbage.
- To do someone out of their due; to deceive or defraud, to cheat (someone).
- To evade, elude.