Proper codes with our crackers (8)
I believe the answer is:
decorous
'proper' is the definition.
(similar in meaning)
'codes with our crackers' is the wordplay.
'with' is a charade indicator (letters next to each other).
'crackers' indicates anagramming the letters (informal term for mad).
'codes' after 'our' is 'ourcodes'.
'ourcodes' is an anagram of 'DECOROUS'.
(Other definitions for decorous that I've seen before include "Proper and well-arranged" , "Fitting" , "Befitting" , "following the proper procedure" , "Suitable" .)