incendiary

Short definition from Wiktionary

Adjective

1. 1
   Capable of, or used for, or actually causing fire.
2. 2
   Of a damaging fire, intentionally caused rather than accidental.
3. 3
   Intentionally stirring up strife, riot, rebellion.
4. 4
   Inflammatory, emotionally charged.

Noun

1. 1
   Something capable of causing fire, particularly a weapon.
2. 2
   One who maliciously sets fires.
3. 3
   One who excites or inflames factions into quarrels.