Order posted for tyrant (6)
I believe the answer is:
despot
'tyrant' is the definition.
('despot' can be a synonym of 'tyrant')
'order posted' is the wordplay.
'order' indicates an anagram.
'posted' anagrammed gives 'DESPOT'.
'for' acts as a link.
(Other definitions for despot that I've seen before include "Cruel and oppressive ruler" , "Tyrant, dictator" , "nasty ruler?" , "Cruel absolute ruler" , "Posted by tyrant" .)