Chess player with renewed energy (5)
I believe the answer is:
white
'chess player' is the definition.
(one of the two players in a game of chess)
'with renewed energy' is the wordplay.
'renewed' is an anagram indicator.
'energy' becomes 'e' (physics symbol as in E=mc2).
'with' with letters rearranged gives 'whit'.
'whit'+'e'='WHITE'
(Other definitions for white that I've seen before include "Pallid" , "wine" , "Snow-coloured" , "- Christmas, famous song" , "Neutral colour" .)