diminisher

plural diminishers

1. One who, or that which, diminishes something.

   But there is yet that which is worſe, the ſpirit of man is not only a diminiſher of his ioy.

   1633, Peter Charro, translated by Samson Lennard, Of Wisdome

   1 more example

   They were also employed in coining of our money; but were accused of being likewise great clippers or diminishers of it, although strongly recommended to our Kings by the Popes, as may be supposed, for their own ends.

   1801, Adam Anderson, William Combe, An historical and chronological deduction of the origin of commerce