-(ə)nə(r) noun
( -s )
: one that softens: as
a. : a worker who softens hides, skins, or leather usually by immersing or tumbling them in water
b. : a textile worker who waxes thread and yarn
c. : a machine or apparatus in which something is softened
d. : a substance added to something (as hard water, molten iron, or rubber in the process of manufacture) to make it soft, malleable, or plastic — compare plasticizer