Kent played with old symbol (5)
I believe the answer is:
token
'symbol' is the definition.
(I know that token is a type of symbol)
'kent played with old' is the wordplay.
'played with' indicates an anagram (letters playing around).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'kent' with its letters anagrammed with 'o' gives 'TOKEN'.
(Other definitions for token that I've seen before include "Representative item" , "Nominal, slight" , "Something of sentimental value" , "Voucher (for, eg, books)" , "Symbol; metal disc" .)