liquefacient noun 2adjective 1forms 1 noun2 •That which serves to liquefy. •(no longer used) Any agent, such as mercury, iodine, etc., that promotes the liquefying processes of the system, and increases the secretions.potassium hydroxide is a liquefacient of tissuessodium bicarbonate is a liquefacient to promote the expulsion of the false membrane. adjective1 •That liquefies. formsliquefacients