Russian ruler turning up with a wearer of dreadlocks (5)
I believe the answer is:
rasta
'wearer of dreadlocks' is the definition.
(Rastafarians wear dreadlocks)
'russian ruler turning up with a' is the wordplay.
'russian ruler' becomes 'tsar' (I've seen this before).
'turning up' says the letters should be written in reverse.
'with' says to put letters next to each other.
'tsar' back-to-front is 'rast'.
'rast'+'a'='RASTA'
(Other definitions for rasta that I've seen before include "Jamaican cult follower (informally)" , "A certain believer" , "One dreaded" , "black believer" , "Adherent of sect originating in Jamaica" .)