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