softener

n [U, C] chemical substance used for softening hard water; device using this 硬水软化剂; 硬水软化器.

sofa, soft, soft currency, soft drug, soft fruit, soft landing, soft option, soft palate, soft porn, soft shoulder, soft soap, soft-boiled, soft-drink, soft-hearted, soft-heartedness, soft-pedal, soft-soap, soft-spoken, softball, soften, softish, softly, softness, software, softwood, softy (also softie), soggily, sogginess, soggy, soh, soigne, soil, soiree, sojourn, sol, sol-fa, solace, solar, solar cell device, solar plexus,