The Collaborative International Dictionary
Dequantitate
Dequantitate \De*quan"ti*tate\, v. t. [L. de- + quantitas,
-atis. See Quantity.]
To diminish the quantity of; to disquantity. [Obs.]
--Sir T.
Browne.
Wiktionary
dequantitate
vb. (context obsolete rare English) To diminish the quantity of.