The most common and most likely answer to this crossword clue is the 7 letter word STEALTH
I've seen this crossword clue in The Times
S
T
E
A
L
T
H
More clues leading to the result STEALTH
- Being broke, latest introduction of HMRC could be newish sort of tax
- Furtiveness of waterbird accommodated in south
- Half-inch tip cut from article in secrecy
- Slyness of the salt at sea
- The last crooks to display cunning
- Secrecy at hostel, somehow giving nothing away
- Secrecy as periosteal thrombus suppressed
- Secrecy the last resort
- The last busy cat-burglar’s speciality
- Covert behaviour‘s appropriate, though heartless
Buddy explains!

The straight part
We know that "Secrecy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case secrecy = stealth.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 STEALTH mean?
STEALTH noun- The attribute or characteristic of acting in secrecy, or in such a way that the actions are unnoticed or difficult to detect by others.
- An act of secrecy, especially one involving thievery.
- To conceal or infiltrate through the use of stealth.
- To have sexual intercourse without a condom through deception (for example, removing the condom mid-act).
- Of a transgender person, hiding their transgender status from society after transition.