blæk ˈkɔːstɪk

mɔː(ɹ)dənt mɔː(ɹ)dənt vɪtɹɪˈɒlɪk of a substance, especially a strong acid; capable of destroying or eating away by chemical action harshly ironic or sinister black humor a grim joke grim laughter fun ranging from slapstick clowning … to savage mordant wit a substance used to treat leather or other materials before dyeing; aids in dyeing process