When water is heated above its boiling point but not turned into vapor or steam, its temperature continues to rise. However, the water remains in the liquid state as long as it is under normal atmospheric pressure.
As the temperature of the water increases, the average kinetic energy of its molecules also increases. This results in faster molecular motion, which leads to an increase in temperature. However, the water molecules are still bound together by intermolecular forces, such as hydrogen bonding, preventing them from escaping as vapor.
At higher temperatures, close to or above the critical point of water (374 degrees Celsius or 705.2 degrees Fahrenheit at normal atmospheric pressure), the distinction between liquid and gas becomes less clear. The water reaches a state known as the supercritical fluid, where it exhibits properties of both a liquid and a gas. In this state, the density and viscosity of the water decrease significantly, and it becomes more similar to a gas.
It's worth noting that heating water above its boiling point without it turning into vapor can be achieved by increasing the pressure instead of the temperature. This is how pressure cookers work, for example. By increasing the pressure, the boiling point of water is raised, allowing it to reach higher temperatures without converting into steam.