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.
míwa
adjective. small, tiny, frail
-(n)ikka
suffix. small
A suffix used in Demonstrative, Relative, and Correlative Stems (DRC) from 1948 to form correlatives for smallness in quantity or amount, such as ᴹQ. manikka “how small, ✱how little” and ᴹQ. tanikka “✱that small, that little” (PE23/108). Tolkien specified that it was “only used in interrogatives and demonstratives”. It was probably related to diminutive ✶-i(n)ki and the root √-NIK “small”.
mitsa
adjective. small
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 word in The Etymologies of the 1930s appearing beside N. mîw “small, tiny, frail” under the root ᴹ√MIW (EtyAC/MIW²). The language is not marked, but it is probably Quenya with a meaning similar to its Noldorin equivalent.