High-tech concession disliked restricting one's time in charge (13)
I believe the answer is:
sophisticated
'high-tech' is the definition.
(similar in meaning)
'concession disliked restricting one's time in charge' is the wordplay.
'concession' becomes 'sop' (sop is a kind of concession).
'disliked' becomes 'hated' (hating is a kind of disliking).
'restricting' indicates putting letters inside.
'one's' becomes 'I's' (Roman numeral).
'time in charge' becomes 'tic' (this could be a standard abbreviation I've not previously seen).
'is'+'tic'='istic'
'hated' enclosing 'istic' is 'histicated'.
'sop'+'histicated'='SOPHISTICATED'
(Other definitions for sophisticated that I've seen before include "Cosmopolitan" , "very complicated" , "Showing knowledge of fashion and culture" , "Cultured; refined" , "Urbane" .)