New fashioned service (6)
I believe the answer is:
modern
'new' is the definition.
(synonyms)
'fashioned service' is the wordplay.
'fashioned' becomes 'mode' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'service' becomes 'RN' (abbreviation for Royal Navy).
'mode'+'rn'='MODERN'
Can you help me to learn more?
(Other definitions for modern that I've seen before include "See 11" , "Belonging to the present or recent times" , "Novel" , "Present-day" , "Recent, up to date" .)