A person or thing that has nothing of substance or permanence within or imprinted upon him, her, or it, such that it can be easily filled with entirely new things. Refers to a painter's canvas that has yet to be painted on. Children's minds are blank canvasses, so we have to be sure to provide them with enriching education and opportunities so as to give them the best possible future. I love moving into a new house and having a blank canvas to make my own! These freshmen are all blank canvasses—we can get them to believe anything we tell them!