Instruct class (5)
I believe the answer is:
order
I believe this is a double definition.
'instruct' is the first definition.
(to instruct is to give orders)
'class' is the second definition.
(I've seen this in another clue)
(Other definitions for order that I've seen before include "Command; neatness" , "Type of column" , "rule of law" , "Regulation" , "Instruct" .)