A question remains : were _Axantur_ *'Theologian', and _Nolondil_
*'Philosopher' Númenorian Proper Names only or also lexemes of
I don't remember that an Elf ever bore a name in _-ndur_, or _-ndil_
in the Corpus, only Númenoreans did.
Then, _Nolondil_ (< _ñolo-ndil_) was a Proper Name used by
Númenoreans, not a lexeme of Quenya, used for a 'philosopher',
as far as I can tell.
We have other names in _-tur_ 'master, lord', _Ciryatur, Sorontur,
Minyatur_, etc. But then _-tur_ is not used as a suffix in Quenya
word-formation only as a base (_turkildi_, V:47; _Turko_, XII:352).
Then again, _Axantur_ was a Proper Name used by Númenoreans
(? and maybe Elves), not a lexeme of Quenya.
[I don't see any compelling reason to suppose that _axantur_
and _nolondil_ were not simply the usual common nouns used
in Quenya to mean 'theologian' and 'philosoper'. I cannot find
any examples of a common noun ending in _-(n)tur_, though
this is not necessarily an indication that this suffix was only used
in personal names. Quenya unquestionally _did_ form common
nouns with _-ndil_ and _-ndur_, e.g., _arandil_ 'king's friend,
royalist' and _arandur_ 'king's servant, minister' (L:386).
A note to "The Shibboleth of Fëanor" states that "Nerdanel's
father was an 'Aulendil' [> 'Aulendur']" (XII:365), and the use
of the indefinite article _an_ before _Aulendil/Aulendur_ seems
to indicate that this was perceived as a common noun, though
capitalized since it begins with a proper name. (_Aulendur_ is
glossed "'Servant of Aulë', sc. one who was devoted to that
Vala".) Compare English _Luddite_ 'a person opposed to new
technology', a common noun capitalized because it derives
from the name of Ned _Lud_, an early opponent of technology
notorious for destroying machinery.
The same note cited above shows that some Elves did bear
personal names in _-ndil_, for it is said that Nerdanel's father
Sarmo was more widely known as _Urundil_ 'copper-lover'
(XII:366). But there seems no doubt that the endings _-ndil_,
_-ndur_ were far more frequently used in the formation of the
names of Men than they were in the names of Elves. -- PHW]