These are commonly called "states of matter."
A gas is compressible.
A liquid is much less compressible but cannot put any resistance against a sheer force. You can imagine this as a cylinder of liquid and you grab two points and force them sideways and it moves without any resistive force.
A solid is also not very compressible but if you grab a bar of a solid and try to force each hand in different directions it will not move much.
A plasma is a special state that is so high temperature that the electrons, protons, and neutrons form a gas cloud. This is sort of like a gas but is a very special state that is formed in special circumstances not common in nature.