Nouns

(n)mordanta substance used to treat leather or other materials before dyeing; aids in dyeing process

Adjectives

(s)black, grim, mordantharshly ironic or sinister“black humor”, “a grim joke”, “grim laughter”, “fun ranging from slapstick clowning … to savage mordant wit”
(s)caustic, corrosive, erosive, vitriolic, mordantof a substance, especially a strong acid; capable of destroying or eating away by chemical action