wash off (something). — phrasal verb with wash us /wɑʃ, wɔʃ/ verb [I/T]. › to ​remove something with ​flowing ​water, or to come off after you do this: She could ​hardly ​wait to wash the ​dirt off. I don’t ​know if this ​paint will wash off. (Definition of wash off (something) from the Cambridge Academic Content Dictionary © Cambridge University Press). Browse.