noun
strange incident; unusual occurrence; rare event
Refers to an event that is out of the ordinary, surprising, or hard to believe. Often used in news or storytelling.
昨夜、近所で珍事が起きた。
A strange incident occurred in the neighborhood last night.
彼が遅刻するなんて珍事だ。
It's a rare event for him to be late.
noun
grave incident; serious accident; unexpected tragedy
Emphasizes the seriousness and unexpectedness of the event. Often written as 椿事 in this sense, though 珍事 is also used.
その椿事は国中に衝撃を与えた。
The grave incident shocked the whole nation.
Compound of 珍 (rare, curious) and 事 (matter, event). The alternative spelling 椿事 uses 椿 (camellia), which is likely ateji based on the reading ちん, though the exact origin is uncertain.