The most common and most likely answer to this crossword clue is the 2 plus 6 letter word IN SECRET
I've seen this crossword clue in Independent
I
N
S
E
C
R
E
T
More clues leading to the result IN SECRET
- Maybe cricket nets touching under cover?
- Runs obtained by English in cricket, perhaps with no-one watching
- Enticers manoeuvring without anybody seeing
- Six-footer entertains soldier surreptitiously
- At home, tight-knit group pens note privately?
- About to be nipped by beetle, say, where you wouldn’t want people to see?
- Centre is repaired privately
- Nobody will capture soldiers covertly
- Nobody keeps soldiers under cover
- Covertly, bug picks up focus of indiscreetness
Buddy explains!
The straight part
We know that "on the sly" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case on the sly = in secret.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.