Power of a military leader on Cyprus (6)
I believe the answer is:
agency
'power' is the definition.
(thesaurus)
'a military leader on cyprus' is the wordplay.
'military leader' becomes 'gen' (general).
'on' means one lot of letters go next to another.
'cyprus' becomes 'cy' (abbreviation).
'a'+'gen'+'cy'='AGENCY'
'of' acts as a link.
(Other definitions for agency that I've seen before include "Business that acts for actors" , "Intervention producing a particular effect" , "Business that conducts business on behalf of others" , "Business that conducts business on behalf of another" , "Employment bureau" .)