Firebug (8)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
arsonist
'firebug' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for arsonist that I've seen before include "A major criminal" , "Pyromaniac" , "One fire-raising" , "Fire raiser" , "Like blazes he will" .)