Lively, fit? Yes, for a change (6)
I believe the answer is:
feisty
'lively' is the definition.
'fit? yes for a change' is the wordplay.
'for a change' is an anagram indicator.
'fit'+'yes'='fityes'
'fityes' anagrammed gives 'FEISTY'.
(Other definitions for feisty that I've seen before include "Spiritedly aggressive" , "Tough" , "Lively; determined" , "Spirited; quarrelsome" , "Spirited and courageous" .)