Symbol of power not concerning one cold philosopher (7)
I believe the answer is:
sceptic
'philosopher' is the definition.
(sceptic is a type of philosopher)
'symbol of power not concerning one cold' is the wordplay.
'symbol of power' becomes 'sceptre'.
'not' suggests deleting specific letters.
'concerning' becomes 're'.
'one' becomes 'i' (Roman numeral).
'cold' becomes 'c' (eg on taps).
'sceptre' with 're' removed is 'scept'.
'scept'+'i'+'c'='SCEPTIC'
(Other definitions for sceptic that I've seen before include "Greek philosopher" , "Disbeliever" , "One who doubts the truth of religions" , "One inclined to question accepted opinions" , "One who doubts accepted opinions" .)