A noun appearing as G. sing “salt” in the Gnomish Lexicon of the 1910s (GL/67), clearly the cognate of ᴱQ. singe “salt” and hence derived from the early root ᴱ√SIŊI (QL/83).
Neo-Sindarin: I’d retain ᴺS. sing “salt” for purposes of Neo-Sindarin as a derivative of the Neo-Root ᴺ√SIÑGI.
A word appearing as G. singrin “salt (aj.)” in the Gnomish Lexicon of the 1910s, an adjective form of G. sing “salt” (GL/67).
Neo-Sindarin: I’d adapt this word as ᴺS. singren “salt[y]” for purposes of Neo-Sindarin using a more common Sindarin adjective suffix.