Rarer

Cavities have become rarer in the developed countries and more people will be able to eat with their own teeth throughout their life.

True friendships are even rarer than diamonds.

When Hadrian was emperor, capital punishment became rarer.

Type Ia supernovae are much rarer, happening roughly once every 500 years in the Milky Way.

I need a rarer kanji.

He buys and sells new, used, and old books. The rarer ones, out-of-print editions, are quite expensive.

Unfortunately, even in the palmiest days of the old Cockermouth, Keswick & Penrith Railway Company, passengers were few and far between at Troutbeck, and since the advent of the motor bus road services they are rarer than ever, and never likely to increase.