The most common and most likely answer to this crossword clue is the 5 plus 2 plus 1 plus 7 letter word CLEAN AS A WHISTLE
I've seen this crossword clue in The Times
C
L
E
A
N
A
S
A
W
H
I
S
T
L
E
More clues leading to the result CLEAN AS A WHISTLE
- Totally innocent, listen as each law is broken
- Reform of laws, sane, ethical and immaculate
- Involved in nothing illegal? Breaking the law in nearly all cases!
- Fair game entering a trade with nothing incriminating
- Very clear signal needed after damaged canals are emptied
- “Flawless Salah toying with Newcastle” – Independent claimed
Buddy explains!
The straight part
We know that "Totally innocent" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case totally innocent = clean as a whistle.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.