"Rarefying" is a word in ENGLISH

To make thin or less consistent; to render less viscid or dense; to rarefy. Specifically: To subtilize, as the humors …

Made thin or less viscid; rarefied.

The act of attenuating; the act of making thin or less dense, or of rarefying, as fluids or gases.

The treatment of disease by inhalations of compressed or rarefied air.

The act or process of rarefying; the state of being rarefied; -- opposed to condensation; as, the rarefaction of air.

Capable of being rarefied.

of Rarefy

To make rare, thin, porous, or less dense; to expand or enlarge without adding any new portion of matter to; …

To become less dense; to become thin and porous.