A noun for “claw, talon” appearing in rough notes on Elvish Hands, Fingers and Numerals from the late 1960s based on the root √NAP “grasp, seize quickly” (VT47/20). In the margin Tolkien wrote a variant form namma with the same glosses, perhaps from *nap-mā and reflecting the earlier (pre-1960) development whereby pm > bm > mm (hat-tip to Vyacheslav Stepanov for this suggestion). If so, nappa may also be derived from *nap-mā, with the (post-1960) development whereby pm > pƕ > pp.

Neo-Quenya: For purposes of Neo-Quenya, I’d stick to nappa, and avoid the question of its origin by assuming it is from *nappā.