A noun appearing as G. thrimp “a stalk” in the Gnomish Lexicon of the 1910s (GL/73), clearly based on the early root ᴱ√SIRIP (QL/84).
Neo-Sindarin: I retain ᴺS. thrimp “stalk” for purposes of Neo-Sindarin, based on an updated Neo-Root ᴺ√THIRIP to better fit Sindarin phonology.
A word appearing as G. sirp “straw” in the Gnomish Lexicon of the 1910s related to G. thripthon “stem” (GL/36, 73). It is likely a cognate of ᴱQ. sirpe “stem, stalk” and hence derived from the early root ᴱ√SIRIPI (QL/84).
Neo-Sindarin: For purposes of Neo-Eldarin, I update this early root to ᴺ√THIRIP, so I would adapted this Gnomish was as ᴺS. thirph “straw” for purposes of Neo-Sindarin.