/ ˈkɔːstɪk; NAmE / adjective
1.
( of a chemical substance ) able to destroy or dissolve other substances
SYN corrosive
2.
critical in a bitter or sarcastic way
SYN scathing :
caustic comments / wit
► caus·tic·al·ly / -kli; NAmE / adverb
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WORD ORIGIN
late Middle English : via Latin from Greek kaustikos , from kaustos combustible, from kaiein to burn.