Gnomish
cuithos
noun. life (period of life); living, livelihood
cuithos hû le mui
a cat and dog life
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 appearing as G. cuithos “life (period of life); living, livelihood” in the Gnomish Lexicon of the 1910s, a noun form of G. cuitha- “am alive” (GL/27).
Neo-Sindarin: For purposes of Neo-Sindarin, I’d update this word to ᴺS. cuithas using the later abstraction noun suffix -as, and would assume it is an abstraction based on ᴺS. cuith “[biological process of] life”. I would use it to refer both to the means of providing for one’s life (= “livelihood”) as well as a period of time within one’s life, as opposed to one’s entire lifetime which would be ᴺS. cuilvorn.