Middle Primitive Elvish
abar
root. *refuser
belē
noun. strength
tū
noun. strength
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 from the 1930s that was an extension of ᴹ√AB “refuse, deny” (Ety/AB). It seems to just be ᴹ√AB(A) with the usual agental suffix -ro added. Its main derivative was Avari, a term that survived into Tolkien’s later writings as the name of the Elves that refused to go to Valinor.