It is not rare that she leaves her umbrella behind.

I prefer my steak rare.

Ah, now I remember. I used a condom; something I rarely, or rather practically never, do.

The sighting of a unicorn is a rareness.

She is raring to go on her vacation.

Rare earth elements are used in the production of high-tech devices.

I had a delicious Welsh rabbit for dinner.

The rarefaction of the gas caused it to expand.

She has a rarefied sense of humor.

The scientist used a special technique to rarefy the gas.