Laze about with enthusiasm (4)
I believe the answer is:
zeal
'laze about with enthusiasm' is the definition.
(I've seen this before)
'laze about' is the wordplay.
'about' indicates anagramming the letters.
'laze' with letters rearranged gives 'ZEAL'.
(Other definitions for zeal that I've seen before include "Fanaticism" , "(Excessive) fervour" , "Laze (anag.)" , "Dedicated enthusiasm" , "Zest, ardour" .)