Tyrant has car to cart off (8)
I believe the answer is:
autocrat
'tyrant' is the definition.
('autocrat' can be a synonym of 'tyrant')
'car to cart off' is the wordplay.
'car' becomes 'auto' ('auto' can be a synonym of 'car').
'off' is an anagram indicator.
'cart' anagrammed gives 'crat'.
'auto'+'crat'='AUTOCRAT'
'has' is the link.
(Other definitions for autocrat that I've seen before include "Ruler liable to 12 ac" , "Dictatorial type" , "All-powerful ruler" , "Actuator (anag) - dictator" , "One person who has unlimited power" .)