A word in the Gnomish Lexicon of the 1910s appearing as G. glaimri “serenity, fair weather”, an abstract noun form of G. glaim “serene, clear, fair (espec. of weather)” (GL/39).
Neo-Sindarin: If adapting this word to Neo-Sindarin, I would make it an abstract noun form based on Neo-Sindarin ᴺS. glaen “serene, fair (weather)”, hence: ᴺS. glaenas “serenity, fair weather”.
An adjective in the Gnomish Lexicon of the 1910s appearing as G. glaim “serene, clear, fair, espec. of weather” (GL/39), a cognate of ᴱQ. kalaina of similar meaning and hence based on the early root ᴱ√KALA [✱ᴱ√GALA] “shine golden” (QL/44).
Neo-Sindarin: I think G. glaim can be salvaged as ᴺS. glaen, since √GAL was still associated with light in Tolkien’s later writings, but I would derive it instead from the root ᴹ√GALAN “bright”, perhaps from ✱g(a)laina.