A Doriathrin adjective meaning “empty” attested only as an element in the name Dor. Mablost (Ety/KAB). Its Quenya cognate lusta suggests a primitive form *✶lustā, with the [o] developing from Ilkorin a-affection. It might be a Doriathrin-only variant of more general Ilkorin losgen “empty”.
Doriathrin
* losgen
adjective. empty
* lost
adjective. empty
An adjective meaning “empty” attested only as an element in the Ilkorin name Mablosgen (Ety/MAP). As suggested by Helge Fauskanger, it might be a combination of Dor. lost and the adjective suffix -en, but if so it is unclear where the medial g came from (AL-Ilkorin/Mablosgen). Alternately, perhaps losgen is the general Ilkorin adjective for “empty” and lost is a variant used only in the Doriathrin dialect.