Wild cat, lithe and muscular (8)
I believe the answer is:
athletic
'muscular' is the definition.
(I've seen this before)
'wild cat lithe' is the wordplay.
'wild' is an anagram indicator.
'cat'+'lithe'='catlithe'
'catlithe' is an anagram of 'ATHLETIC'.
'and' acts as a link.
(Other definitions for athletic that I've seen before include "Lithe cat (anag.)" , "See 12" , "Sporting, vigorous" , "Fit and sporty" , "Fit and strong - football club?" .)