Laze about to show enthusiasm? (4)
I believe the answer is:
zeal
'enthusiasm?' is the definition.
(I know that ardour is a type of eagerness)
'laze about' is the wordplay.
'about' is an anagram indicator.
'laze' is an anagram of 'ZEAL'.
'to show' acts as a link.
(Other definitions for zeal that I've seen before include "(Excessive) fervour" , "Eagerness and devotion" , "Interest that's definitely not diminished" , "6 [ENTHUSIASM]" , "Zing" .)