Quenya 

-ndur

friend

-ndur (also -dur), ending in some names, like Eärendur; as noted by Christopher Tolkien in the Silmarillion Appendix it has much the same meaning as -ndil "friend"; yet -ndur properly means "servant of" (SA:(noun)dil), "as one serves a legitimate master: cf. Q. arandil king's friend, royalist, beside arandur 'king's servant, minister'. But these often coincide: e.g. Sam's relation to Frodo can be viewed either as in status -ndur, in spirit -ndil." (Letters:286)