Middle Primitive Elvish
khaw
root. rest, lie at ease
ezdē
noun. rest
korka
root. crow
sed
root. rest
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.
A root in The Etymologies of the 1930s glossed “crow”, with derivatives ᴹQ. korko and N. corch of the same meaning; it replaced a root ᴹ√KARKA with derivatives ᴹQ. karka and N. carach (Ety/KARKA). The deleted form conflicted with contemporaneous ᴹ√KARAK “sharp fang, spike, tooth” (Ety/KARAK). This deleted form nevertheless may be connected to S. crebain from The Lord of the Rings (LotR/285), whose singular craban “bird of crow-kind” (PE17/37) might be derived from ✱k(a)rak-wan.
There is another primitive form ✶k(a)wāk used as the basis for “crow” in the Quendi and Eldar of 1959-60 (WJ/395), but even later this primitive form was the basis for Q. quácë “frog” (VT47/36); see the entry on √KAWAK for discussion. As a result, I think earlier ᴹ√KORKA is probably the best choice for “crow” words for the purpose of Neo-Eldarin.