Dictator's person vetting design of squares (7)
I believe the answer is:
chequer
'design of squares' is the definition.
'chequer' can be an answer for 'design' (I've seen this before). I'm not certain of the 'of squares' bit.
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for chequer that I've seen before include "Divide into alternately coloured squares" , "design" , "Mark into squares of different colours" , "last man on board" , "Alternation of colours" .)