(of language) nasty; harsh, sharp
His review of my new book contains some really caustic comments.
kaiein (to burn) (Greek)
abrasive, caustic, sardonic, trenchant, vitriolic, vituperative
caustic soda is very common and its "harmful " for health if taken in large quantity. therefore caustic means harmful or burning. Since its a soda its somehow related with chemistry as well. sounds like 'caution'. meaning, be careful, there is something. that is corrosive. or. 'can cause corrosion'.