im (“between, within”) + loth (“a head of small flowers”), mel (“dear”) + ui (adjective suffix) #M sometimes resists lenition when otherwise may cause confusion.
Sindarin
imloth melui
place name. Lovely or Sweet Flower-valley
Imloth Melui
noun. sweet flower valley
Imloth Melui
Imloth Melui
The name Imloth Melui is translated as "sweet flower-valley".
A rose-filled valley in Gondor (LotR/866) translated “Lovely Flowery Vale” (RC/582) or “Sweet Flower-valley” (VT42/18), a combination of †im “valley” and loth “flower” (VT42/18) with otherwise unattested melui “lovely”. In this position, an adjective like melui would ordinarily undergo soft mutation to velui, but in notes from around 1969 Tolkien indicated this was an example of the graduation loss of m-mutation in late Sindarin (PE23/138 note #12).
Conceptual Development: In Lord of the Rings drafts from the 1940s, this name was already N. Imloth Melui.