ᴺS. [G.] ^glaen adj. “serene, clear, fair (espec. of weather)” (Category: 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√KALA¹ [*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.
References ✧ GL/39