Rubbery things have a tough, flexible texture, like a rubbery playground ball or a rubbery piece of American cheese.
You'll often find the adjective rubbery describing food that's unpleasant to chew, like rubbery pasta or overcooked, rubbery chicken. Things actually made out of rubber are rubbery too, like a rubbery water balloon or the pair of rubbery gloves your grandma uses for gardening. Rubbery comes from rubber, a noun that originally meant "an eraser made from a tropical plant," or in other words, "a thing that rubs."