caustic

nouns

any chemical substance that burns or destroys living tissue
is a type of (narrower)
(chemistry) a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight

adjectives

harsh or corrosive in tone
"an acerbic tone piercing otherwise flowery prose"; "a barrage of acid comments"; "her acrid remarks make her many enemies"; "bitter words"; "blistering criticism"; "caustic jokes about political assassination, talk-show hosts and medical ethics"; "a sulfurous denunciation"; "a vitriolic critique"
of a substance, especially a strong acid; capable of destroying or eating away by chemical action