Vaporous (adjective)

1. Resembling or consisting of vapor; misty or hazy.
2. Having a tendency to evaporate quickly; fleeting.

Origin:

Early 17th century: from latin vaporosus, from vapor "steam, vapor".

Examples:

1. The sky was full of vaporous clouds.
2. The lake was surrounded by a vaporous mist.
3. A vaporous substance is one that is in the form of a gas or a vapor.
4. The feeling of love can be vaporous and hard to define.
5. The memory of the event was still vaporous in his mind.