I set fire ablaze, being more spirited (8)
I believe the answer is:
feistier
'more spirited' is the definition.
('feisty' can be similar in meaning to 'spirited')
'i set fire ablaze' is the wordplay.
'ablaze' is an anagram indicator (letters get excited or ablaze).
'i'+'set'+'fire'='isetfire'
'isetfire' anagrammed gives 'FEISTIER'.
'being' is the link.
(Other definitions for feistier that I've seen before include "More spirited" , "More pugnacious" .)