Qenya
ango
noun. snake, dragon, snake, dragon, *serpent
lango
noun. throat
angulóke
noun. dragon
lanko
noun. throat
lungu
noun. dragon
lóke
noun. dragon
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 noun in The Etymologies of the 1930s glossed “snake” derived from the root ᴹ√ANGWA of the same meaning, with a plural form angwi (Ety/ANGWA). This plural form reappeared in the Quenya Verbal System (QVS) from 1948, but there it was translated “dragons”.
Conceptual Development: A similar form ᴱQ. oqi “snake” appeared in the Qenya Lexicon and Poetic and Mythological Words of Eldarissa of the 1910s as a derivative of the early root ᴱ√OQO “curve, bend” (QL/70).
Neo-Quenya: The word Q. leuca “snake” from The Lord of the Rings appendices is more commonly used for “snake” in Neo-Quenya. I would limit ango to larger snakes, meaning “serpent” in keeping to its use for “dragons” as well.