A gas, liquid, semi-liquids and semi-solids can take the shape of the container it's placed in.
Unlike the atoms of solid, the attraction forces between the atoms of gases, liquid, semi-liquids, and semi-solid are much weaker. Hence, making them loosely held together and unable to hold a static form.
However, in the case of semi-solid (like soft clay), they can maintain a constant shape but their "resistance" to external forces is very weak, rendering them vulnerable to any change in shape.
State of Matter