The usual Sindarin word for “death”, derived from the root √ÑGUR of similar meaning (UT/39; Ety/ÑGUR).
Conceptual Development: This word dates all the way back to the Gnomish Lexicon of the 1910s (GL/43), anchored by well established names like Gurthang or Gurtholf(in), the name of Túrin’s sword. Tolkien experimented with various alternate forms over the years, such as G. urthu (GG/14), G. gurthu (GL/43), ᴱN. gurdh (PE13/146) and N. guruth (Ety/ÑGUR), but kept coming back to gurth as the basic form.
Neo-Sindarin: For purposes of Neo-Sindarin, I would use this word for death in general and especially violent death, as opposed to the more euphemistic [N.] gwanath or gwanu “death”, more literally “departure”.
A word for “heart (inner mind)” in notes from the late 1960s, equivalent to Q. órë (VT41/11). In the original article published in VT41 in July 2000, Carl Hostetter gave its primitive form as ʒōrē, but in his later book The Nature of Middle-Earth published in 2021, he corrected this to gōrē (NM/219).
Conceptual Development: Early Noldorin word-lists from the 1920s had N. gir glossed “interior, centre, inwards, inner parts” (PE13/144) or “inwards, interior, inside, heart” (PE13/161).