gas

Informal. Empty or boastful talk.

"Don't pay any attention to him, it's all just gas."

A substance in a state neither solid nor liquid, having no fixed shape and having the ability to expand indefinitely.

"The air we breathe is a mixture of gases."

To poison or overcome with gas.

"The soldiers were gassed during the war."

A flammable gas used as a fuel.

"The gas bill was very high this month."