The most common and most likely answer to this crossword clue is the 6 letter word SHARIA
I've seen this crossword clue in The Guardian
S
H
A
R
I
A
Buddy explains!
The straight part
We know that "the law" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case the law = sharia.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 SHARIA mean?
SHARIA noun- Traditional Islamic religious law primarily based on the Quran, but also the hadith and tafsir; it covers the totality of religious, political, social and private life, making no distinction between religion and life – in other words between transgressions of moral rules (sin) and of social rules.