Name of Emyn Duir after it became the haunt of evil creatures, translated “Mountains of Mirkwood” (UT/280), but more literally “Mountains under Night” (UTI/Emyn-nu-Fuin). This name is a combination of the plural of amon “hill”, the preposition nu “under” and the noun fuin “night”.
noun. mountains under night
place name. Mountains of Mirkwood, (lit.) Mountains under Night
emyn (pl. of amon “hill”) + nu (“under”) + fuin (“dead of night, gloom, darkness”)