Starts with the straight approach — right for tyrant (4)
I believe the answer is:
'tyrant' is the definition.
(I've seen this before)
'starts with the straight approach right' is the wordplay.
'starts with' indicates taking the first letters.
The initial letters of 'the straight approach right' is 'TSAR'.
'for' acts as a link.
(Other definitions for tsar that I've seen before include "Peter the Great, for example" , "Person in charge" , "Alexander and Nicholas held this title in Russia" , "Old Russian 22" , "Powerful man" .)