DIRECTION for the question: In the following question, five words have been given out of which four are alike in some manner, while the, fifth one is different. Choose out the odd one.

The odd one out is Vapour.

The logic is based on the state of matter and the process of condensation/precipitation:

Hailstone, Fog, Sleet, and Mist are all forms of water that have already condensed or frozen into liquid or solid states. They are visible manifestations of moisture in the atmosphere.

Vapour (specifically water vapour) is the gaseous state of water and is generally invisible to the naked eye.

Essentially, the other four are products formed from vapour.