Sees anger somehow as enthusiasm (9)
I believe the answer is:
eagerness
'enthusiasm' is the definition.
(eagerness is a kind of enthusiasm)
'sees anger somehow' is the wordplay.
'somehow' indicates anagramming the letters.
'sees'+'anger'='seesanger'
'seesanger' with letters rearranged gives 'EAGERNESS'.
'as' is the link.
(Other definitions for eagerness that I've seen before include "'Keenness, avidness (9)'" , "Keen interest" , "Sense rage (anag.)" , "Avidity" , "Keen attitude" .)