Sure to be confused about a number of laws (5)
I believe the answer is:
rules
'laws' is the definition.
(I know this)
'sure to be confused about a number' is the wordplay.
'to be confused' is an anagram indicator.
'about' means one lot of letters goes inside another.
'a number' becomes 'l' (fifty in Roman numerals).
'sure' is an anagram of 'rues'.
'rues' placed around 'l' is 'RULES'.
'of' acts as a link.
(Other definitions for rules that I've seen before include "strips" , "See 7" , "Conventions" , "following Queensberry?" , "Regulations, precepts" .)