Doriathrin precursor to S. Aelin-uial translated “Twilight Meres” (LR/262). In The Etymologies, it was translated “Veiled Pool” and given as a combination of umboth “large pool” and muilin “veiled” (Ety/MBOTH, MUY).
Doriathrin
muilin
adjective. secret, veiled
umboth muilin
place name. Twilight Meres, Veiled Pool
A Doriathrin adjective meaning “secret, veiled” derived from root ᴹ√MUY (Ety/MUY), apparently a combination of muil “vagueness” and the adjective-suffix -in.