The most common and most likely answer to this crossword clue is the 3 letter word ACE
I've seen this crossword clue in The Times
A
C
E
More clues leading to the result ACE
- Wicked desire to get rid of husband
- Star not entirely graceful
- At regular intervals, watched champion
- Pain yielding hearts — it’s a high card
- Lacking bit of depth, freshwater fish expert
- A church provides one
- Star showing effrontery, female being put off
- A sort of church expert
- Wizard, one in a suit
- Very good one!
Buddy explains!

The straight part
We know that "Very good/one" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case very good/one = ace.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 ACE mean?
ACE noun- A single point or spot on a playing card or die.
- A card or die face so marked.
- The ball marked with the number 1 in pool and related games.
- A very small quantity or degree; a particle; an atom; a jot.
- A serve won without the opponent hitting the ball.
- A single point won by a stroke, as in handball, rackets, etc.
- The best pitcher on the team.
- (19th century) A run.
- A hole in one.
- An expert at something.
- A military aircraft pilot who is credited with shooting down many enemy aircraft, typically five or more.
- A perfect score on a school exam.
- Any of various hesperiid butterflies.
- A quark.
- (US) To pass (a test, interviews etc.) perfectly.
- To win a point by an ace.
- To make an ace (hole in one).
- Excellent.
- A person who is asexual.
- Asexual. (not experiencing sexual attraction)