From the Latin causticus, from Ancient Greek καυστικός, from καυστός + -ικός.

• enPR: kôs'tĭk, kŏs'tĭk, IPA: /ˈkɔːstɪk/, /ˈkɒstɪk/

caustic

1. Capable of burning, corroding or destroying organic tissue.
2. (of language, etc.) Sharp, bitter, cutting, biting, and sarcastic in a scathing way.
   • 1853, Charlotte Brontë, Villette:

     Madame Beck esteemed me learned and blue; Miss Fanshawe, caustic, ironic, and cynical

   • 1897 December (indicated as 1898), Winston Churchill, chapter VIII, in The Celebrity: An Episode, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd., →OCLC ↗:

     The humor of my proposition appealed more strongly to Miss Trevor than I had looked for, and from that time forward she became her old self again; […] . Our table in the dining-room became again the abode of scintillating wit and caustic repartee, Farrar bracing up to his old standard, and the demand for seats in the vicinity rose to an animated competition.

   • c. 1930, W.H.Auden, The Quest:

     though he came too late / To join the martyrs, there was still a place / Among the tempters for a caustic tongue / / To test the resolution of the young / With tales of the small failings of the great

• (capable of destroying tissue) acidic, biting, burning, corrosive, searing
• (severe, sharp) bitchy, biting, catty, mordacious, nasty, sarcastic, scathing, sharp, spiteful, vitriolic

• cauterize
• encaustic
• holocaust
• homocaust
• hypocaust
• ink

• German: zersetzend, beißend
• Italian: caustico
• Portuguese: cáustico
• Russian: е́дкий
• Spanish: cáustico

• German: scharf, beißend, bissig, ätzend, sarkastisch
• Italian: caustico
• Portuguese: cáustico

caustic (plural caustics)

1. Any substance or means which, applied to animal or other organic tissue, burns, corrodes, or destroys it by chemical action; an escharotic.
2. (optics, computer graphics) The envelope of reflected or refracted rays of light for a given surface or object.
3. (mathematics) The envelope of reflected or refracted rays for a given curve.
4. (informal, chemistry) Caustic soda.

• German: Ätzmittel
• Portuguese: cáustico

• German: Kaustik
• Italian: caustica
• Portuguese: cáustica

• German: Kaustik
• Italian: caustica
• Portuguese: cáustica