潤滑

smooth / oily / sleek / to lubricate

surname Hua

to slip; to slide / slippery; smooth / sly; slippery; not to be trusted

moist; glossy; sleek / to moisten; to lubricate / to embellish; to enhance / profit; remuneration / (neologism c. 2021) (slang) (loanword from "run") to emigrate (in order to flee adverse conditions)

lubricating oil

lubricant