Tyrannical Democrat in charge detaining tortured poets (8)
I believe the answer is:
despotic
'tyrannical' is the definition.
(synonyms)
'democrat in charge detaining tortured poets' is the wordplay.
'democrat' becomes 'd'.
'in charge' becomes 'ic' (abbreviation for 'in charge').
'detaining' means one lot of letters goes inside another.
'tortured' indicates anagramming the letters (I've seen this in other clues).
'd'+'ic'='dic'
'poets' with letters rearranged gives 'espot'.
'dic' going around 'espot' is 'DESPOTIC'.
(Other definitions for despotic that I've seen before include "Cruelly oppressive" , "Tyrannical, oppressive" , "domineering" , "Authoritarian" , "Ruling harshly" .)