combust

Short definition from Wiktionary

Verb

1. 1
   To burn; to catch fire.
2. 2
   To erupt with enthusiasm or boisterousness.

Adjective

1. 1
   Burnt.
2. 2
   In close conjunction with the sun (so that its astrological influence is "burnt up"), sometimes specified to be within 8 degrees 30'.

Noun

1. 1
   That which undergoes burning.