Moldable means able to be shaped or formed into different forms. Clay is moldable when it's wet because you can press, squeeze, and sculpt it into a bowl, a figure, or whatever shape you want. Once it dries or gets fired in a kiln, it loses this quality and becomes hard and fixed.

Materials like warm wax, wet concrete, and soft metals like gold are moldable because they can be worked into new shapes.

People sometimes use moldable metaphorically to describe someone whose character or opinions are still forming and easily influenced. A teacher might think of young students as moldable, meaning their minds are open and ready to learn new ways of thinking. But this usage requires care: while children do learn and grow, they're not objects to be shaped. Everyone has their own personality and ideas, even when young.

In science and engineering, whether something is moldable matters enormously. Glassblowers need glass that becomes moldable when heated. Sculptors need materials that stay moldable long enough to work with. The opposite of moldable might be rigid or brittle, describing things that break rather than bend when you try to reshape them.