*√NAM root. “judge”
A root implied by various Quenya words having to do with “judgement” from the 1950s and 60s, most notably Q. Námo “Ordainer, Judge” as the true name of Q. Mandos (S/28), a name that began to appear in document in the early 1950s (PE21/85). The root is evident in other words from this period, such as Q. namna “statute” (MR/258), Q. námië “a single judgment or desire” (VT41/13) and the verb Q. nam- “judge” in the phrase: Q. ore nin karitas nō namin alasaila “I feel moved to do so but judge it unwise” (VT41/13). *√NAM might also be the basis for the second element of the name Q. Rithil-Anamo “Doom-ring”, the circle of thrones where the Valar sat in council (WJ/401).
In notes from 1969 Tolkien seems to have changed his mind of the root for “judge”, writing Q. nemin >> Q. hamin >> Q. navin for “I judge”, and giving a new root √NDAB “to judge” in a marginal note along with a revised name Návo to replace Námo (PE22/154, notes #53 and #55). This new root conflicts with √NDAB “endeavor, try” from earlier in the same bundle of documents (PE22/151).
Neo-Eldarin: For purposes of Neo-Eldarin, I would ignore the late change of *√NAM >> √NDAB “judge”, since *√NAM has more attested derivatives and Námo appears in the published Silmarillion. Also, all of the derivatives of this root are Quenya, and its possible use in the name Rithil-Anamo (coined in Valinor) imply that it might be a root invented after the Elves arrived in Aman. Thus I think it is best to treat it as Quenya-only root, and used ᴹ√BAD “judge” as the basis for (Neo) Sindarin words for judgement by retaining Noldorin words with these meanings from the 1930s (Ety/BAD).