dullifiˈcationn. (in quot.) something that makes one dull).Apparently an isolated use.
ΘΚΠ
the world > physical sensation > physical sensibility > physical insensibility > dullness of sense perception > [noun] > state of physical stupefaction > physically stupefying > that which
duller1620
stupefier1661
intoxicant1757
inebriant1813
stuporific1853
dullification1855
1855 DoranQueens of Eng. II. vii. 275 The princess called her mother's court a ‘Dullification’.