Cryptic clues include a legal stipulation (6)
I believe the answer is:
clause
'legal stipulation' is the definition.
'clause' can be an answer for 'stipulation' (thesaurus). I am not certain of the 'legal' bit.
'cryptic clues include a' is the wordplay.
'cryptic' is an anagram indicator (a cryptic or obscure order of the letters).
'include' is an insertion indicator.
'clues' with letters rearranged gives 'cluse'.
'cluse' enclosing 'a' is 'CLAUSE'.
Can you help me to learn more?
(Other definitions for clause that I've seen before include "Joker, say" , "Separate item in contract" , "Bill's article" , "More than a phrase and not quite a sentence" , "Part of sentence or document" .)