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English definition of “caustic”

caustic

adjective uk   /ˈkɔː.stɪk/ us    /ˈkɑː-/

caustic adjective (CHEMICAL)

describes a chemical that burns or destroys things, especially anything made of living cells: a caustic substanceTypes of chemicalSpecific chemicals, chemical compounds and gasesSubstances and structures in the body

caustic adjective (WORDS)

describes a remark or way of speaking that is hurtful, critical, or intentionally unkind: caustic comments She's famous in the office for her caustic wit.Unkind, cruel and unfeelingViolent or aggressiveTreating people or animals badlyInsults and abuse
caustically
adverb uk   /ˈkɔː.stɪ.kəl.i/ us    /ˈkɑː-/
Unkind, cruel and unfeelingViolent or aggressiveTreating people or animals badlyInsults and abuse
(Definition of caustic from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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