The most common and most likely answer to this crossword clue is the 4 letter word SODS
S
O
D
S
Buddy explains!
The straight part
We know that "sort of law" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sort of law = sods.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 SODS mean?
SODS verb- To cover with sod.
- Sodomite; bugger.
- (mildly pejorative, formerly considered vulgar) A person, usually male; often qualified with an adjective.
- Any trifling amount, a bugger, a damn, a jot.
- Bugger; sodomize.
- Damn, curse, confound.
- A damper (bread) which has failed to rise, remaining a flat lump.
- The rock dove.