What does "rareness" mean?

The property of being rare; rarity

What is a synonym for "rareness"?

Common synonyms include: infrequency, rarity, airiness, dearth, immateriality, incorporeality.

noun

noun ·2 syllables ·Rare ·Advanced level

Noun

1
The property of being rare; rarity countable, uncountable
"We discussed the rareness of the coin and decided it was actually pretty common."
2
noteworthy scarcity wordnet

"We discussed the rareness of the coin and decided it was actually pretty common."

From rare + -ness.