Feel passionate, then unusually good (7)
I believe the answer is:
enthuse
'feel passionate' is the definition.
'then unusually good' is the wordplay.
'unusually' indicates anagramming the letters.
'good' becomes 'use' (in phrases like 'it's no good', 'any good?' etc).
'then' with letters rearranged gives 'enth'.
'enth'+'use'='ENTHUSE'
(Other definitions for enthuse that I've seen before include "Seem keen" , "Express eager enjoyment, interest or approval" , "Excite - show excitement" , "Show passionate zeal (about something)" , "Show great interest" .)