Early Quenya
-léni
suffix. long
-lénu
suffix. long
anda
adjective. long
andra
adjective. long
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 suffix for “long” in the Qenya Lexicon of the 1910s with variants lēni or lēnu, both base on the early root ᴱ√LENE “long” (QL/53). These Qenya suffixes were also mentioned in the contemporaneous Gnomish Lexicon (GL/39).