A noun appearing as S. laudh “gluttonous eating” in the Outline of Phonology (OP2) from the 1950s from primitive {✶labdā >>} ✶labdē (PE19/91-92 note #110). It also appeared as N. lauð in Outline of Phonetic Development (OP1) from the 1940s with the glosses “licking up (food or drink), gluttonous eating”, the first of these presumably the original (archaic?) meaning (PE19/45). In OP2, the section where it appeared was marked through when Tolkien revised the Quenya phonetic developments, but the Sindarin phonetic developments remain sound, so I’d retain ᴺS. laudh “gluttonous eating” for purposes of Neo-Sindarin.
Sindarin
laud
noun. feather
laudh
noun. gluttonous eating
laudh
noun. licking up
Dor. licking up, gluttonous eating
laud
noun. tide, motion of the sea; flood; high tide
laudh
noun. gluttonous eating, [N.] †licking up (food or drink)
pess
noun. feather
A Sindarin word for “feather”, attested only its suffixal form -lod in the name gwaelod “wind feather” (PE23/142). It is derived from ✶lauto, so its Sindarin singular form would be ✱laud.