Order giving rise to rubbish joke (6)
I believe the answer is:
diktat
'order' is the definition.
(I've seen this before)
'rise to rubbish joke' is the wordplay.
'rise' is a reversal indicator.
'to rubbish' becomes 'tat' (low-quality items or material).
'joke' becomes 'kid' (I've seen this before).
'tat'+'kid'='tatkid'
'tatkid' in reverse letter order is 'DIKTAT'.
'giving' acts as a link.
(Other definitions for diktat that I've seen before include "Categorical statement" , "Strict order" , "Order allowing no opposition" , "Dogmatic statement" , "Forceful order that must be obeyed" .)