Aggravate, intensify (7)
I believe the answer is:
inflame
I believe this is a double definition.
'aggravate' is the first definition.
(I know that inflame is a more specific form of the action aggravate)
'intensify' is the second definition.
(thesaurus)
(Other definitions for inflame that I've seen before include "Exacerbate" , "Provoke to anger" , "Excite passionate feelings" , "Incite" , "Make (a situation) worse" .)