mordant
mor-dant
noun
A substance used to fix dyes or etch metal.
"They used a mordant to prepare the fabric for dyeing."
adjective
Having a sharp, critical, or sarcastic quality, often with biting wit.
"Her mordant wit often made others squirm."
Thesaurus
Synonyms: grim, sarcastic, black, destructive, vitriolic, erosive, caustic, corrosive