The most common and most likely answer to this crossword clue is the 7 letter word BETRAYS
I've seen this crossword clue in The Guardian
B
E
T
R
A
Y
S
Buddy explains!
The straight part
We know that "Exposes" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case exposes = betrays.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 BETRAYS mean?
BETRAYS verb- To deliver into the hands of an enemy by treachery or fraud, in violation of trust; to give up treacherously or faithlessly.
- To prove faithless or treacherous to, as to a trust or one who trusts; to be false to; to deceive.
- To violate the confidence of, by disclosing a secret, or that which one is bound in honor not to make known.
- To disclose or indicate, for example something which prudence would conceal; to reveal unintentionally.
- To mislead; to expose to inconvenience not foreseen; to lead into error or sin.
- To lead astray; to seduce (as under promise of marriage) and then abandon.