Gnomish
rig
noun. a snarl, a sneer
rig-
verb. to twist, contort
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 verb appearing as G. rig- “twist, contort” in the Gnomish Lexicon of the 1910s (GL/65). It was clearly based on the early root ᴱ√RIKI from the contemporaneous Qenya Lexicon of similar meaning; compare ᴱQ. riqi- “wrench, twist” (QL/80). The Gnomish verb had a longer variant rictha- “contort, twist” which also had an extended meaning “confuse, disarrange, upset”.
Neo-Sindarin: The root √RIK “twist” survived in Tolkien’s later writings, so I would retain ᴺS. rig- “to twist, contort” for purposes of Neo-Sindarin, but I would also give it the extended meaning “✱to confuse, disarrange, upset” from its longer Gnomish variant.