seldom
adj.-
1 rare (adj.) C1 Advanced Archaic Literaryrare or not happening very much.
occurring or appearing infrequently; rare.
ExampleThe museum only shows these seldom seen paintings once a year.
ExampleThe scholar spent years researching the seldom visited archives of the remote monastery to find the original manuscript.
UsageIn modern English, this is almost exclusively used as an adverb; the adjective form is restricted to specific literary contexts.
From late Middle English seldom, alteration of earlier selden by analogy with adverbial datives such as whilom, from Old English seldan (“seldom”), from Proto-West Germanic seldanā, from Proto-Germanic seldanē. Cognate with Saterland Frisian säilden (“seldom”), West Frisian selden, komselden (“rare, seldom”), Dutch zelden, German selten, Danish sjælden, Norwegian Bokmål sjelden, Norwegian Nynorsk sjeldan, Swedish sällan, Faroese sjáldan, Icelandic sjaldan. More at seld and selly.