The most common and most likely answer to this crossword clue is the 2 plus 3 plus 3 letter word ON THE DOT
I've seen this crossword clue in Financial Times
O
N
T
H
E
D
O
T
More clues leading to the result ON THE DOT
- Not terribly keen about final decision-maker? Precisely!
- Exactly above the “eye”, did you say?
- Not terribly keen about news boss being sharp
- Work to do, then, promptly
- Exact time when sentence ends
- May, perhaps: leader deposed by party taken in by exotic creature? Exactly
- Month we’d got starters out punctually
- Decayed tooth end is sharp
- Precisely where the telegraphist may be concentrating?
- Tooth end repaired exactly when agreed
Buddy explains!

The straight part
We know that "sharp" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sharp = on the dot.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.