Early Primitive Elvish
sḷkḷ
root. rich, lush
sḷkḷ
root. *grass, mow
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
ᴱ√SḶKḶ² “rich, lush” was variant of the root ᴱ√SṚKṚ “fat” in the Qenya Lexicon of the 1910s with derivatives ᴱQ. silk(in)a “rich, fat, glossy” and ᴱQ. silqe “gloss hair” (QL/86), possibly the same as ᴱ√SḶKḶ from which “grass” words were derived (QL/84). In The Etymologies of the 1930s, ᴹ√SALAK was used exclusively of “grass” words.