Severely critical or sarcastic in speech; harshly bitter. In chemistry, able to burn or corrode organic tissue.
From Greek 'kaustikos' meaning burning, from 'kaiein' (to burn). Originally used for substances that burn or corrode, later extended metaphorically to describe burning, harsh speech.
Think 'COST-ic' - caustic comments COST relationships because they burn! Or remember it sounds like 'caustic soda' - both the chemical and caustic words can burn.
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