rarityEnglishOxford English Thesaurusrarity noun 1 the rarity of earthquakes there has lulled people into a false sense of security: infrequency, rareness, unusualness, uncommonness, singularity, uniqueness; scarcity, scarceness, sparseness. 2 steam locomotives are now becoming something of a rarity: collector's item, rare person/thing, rare bird, marvel, wonder, nonpareil, one of a kind, find, conversation piece; curiosity, oddity, anomaly, freak; outlier, edge case; Latin rara avis; British, informal one-off, oner.rarity Oxford Dictionary of English