Gnomish
gochestri
noun. consanguinity
gochethri
noun. consanguinity
hestri
noun. consanguinity
hethri
noun. consanguinity
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 word in the Gnomish Lexicon of the 1910s glossed “consanguinity”, an abstract noun formation from †hest “brother or sister” with variants hestri and hethri (GL/49). It also had variants G. gochestri and gochethri with the prefix G. go- “together” (GL/40).