Middle Primitive Elvish
karani
adjective. red
karan
root. red
kuldā
adjective. red
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.
This root appeared in The Etymologies of the 1930s glossed “red” (Ety/KARÁN), a later iteration of ᴱ√KṚN of the Qenya Lexicon of the 1910s of the same meaning, but with syllabic ṛ (QL/48). Its main Quenya derivative, Q. carnë, retained the same form throughout Tolkien’s life, but its Gnomish forms G. carn(in) “scarlet” and G. crintha “rosy, pink” (GL/25, 27) became N. caran “red” in the 1930s, and retained that form thereafter.