Clue: Ruler after revolution dreads possessor confiscating article (4)
Answer: TSAR
Explanation: Definition: Ruler
 **Reversal of**(after revolution …) ["Rasta"(short for a Rastafarian who has/possesses dreads/dreadlocks) **minus**(confiscating) "a"(an article in grammar)].
Defn: …/emperor of Russia, formerly.