In chemistry, a solvent is the liquid that does the dissolving. When a lyophobic substance is placed in a solvent, it resists forming a colloid. A colloid is a mixture where tiny particles are scattered through a liquid.
Because the particles do not attract the solvent molecules, they tend to clump together. This constant clumping makes the chemical mixture very unstable over time. If you add a tiny amount of salt, the particles will quickly separate and sink.
Heating or shaking the liquid can also cause the particles to fall out. You cannot make a lyophobic mixture just by stirring the two materials together. Instead, chemists must use special chemical reactions to force the particles apart.
They might also use strong mechanical mixing to achieve the same goal. Even after this effort, the resulting mixture constantly wants to separate. A common student misconception is that lyophobic means exactly the same thing as hydrophobic.
Hydrophobic is a specific term that means a substance repels water. Lyophobic is a broader term that applies to any liquid solvent.