The most common and most likely answer to this crossword clue is the 8 letter word LEGALISE
I've seen this crossword clue in The Daily Telegraph
L
E
G
A
L
I
S
E
More clues leading to the result LEGALISE
Buddy explains!
The straight part
We know that "Put within confines of the law" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case put within confines of the law = legalise.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 LEGALISE mean?
LEGALISE verb- To make legal or permit under law. Either by decriminalising something that has been illegal or by specifically permitting it.