According to the Oxford Dictionary the word holocaust means "to sacrifice oneself completely".

The root -holo means "whole, entire, complete". From Greek -holos means the same.
Other words with the root -holo are Holocryptic, hologram, holograph.
The root -caustic means "burning, corrosive," from Latin causticus "burning, caustic," from Greek kaustikos "capable of burning; corrosive," from kaustos "combustible; burnt".
Other words with the root -caustic are Catacaustic, causticity.
