detrectator
From LSJ
μηδὲν κοτυλίζειν, ἀλλὰ καταπάττειν χύδην → not to sell by the cupful, but to dole out indiscriminately | not to sell by retail but wholesale
Latin > English (Lewis & Short)
dētrectātor: (dētract-), ōris, m. id.. *
I One who declines or refuses: ministerii, Petr. 117, 11.—
II A diminisher, disparager: laudum suarum, Liv. 34, 15, 9: honorum, Aus. Idyll. 2, 51.