Short instruction (5)
I believe the answer is:
brief
I believe this is a double definition.
'short' is the first definition.
(similar in meaning)
'instruction' is the second definition.
(thesaurus)
(Other definitions for brief that I've seen before include "Brusque - lawyer (slang)" , "Provide someone with the facts of the case" , "Short - work for a barrister" , "Document stating the facts of a legal case" , "Succinct" .)