§ Rimbedir >> Padathir (RS:194,198,361)
§ Du-finnion (RS:361)
§ Ethelion ’Peregrin’ (RS:392,395)
These are Elvish names of Trotter, whose character later became Aragorn, but was originally conceived as a hobbit. For a detailed analysis see Lambengolmor #915 and #918 [1].
In short, there are two possibilities for Rimbedir – #rim- ’frequent’ (RIM-) + lenited #pedir, an agentive formation from pata- ’walk’, as in S. aphad- ’follow’ < ap-pata ’walk behind, on a track or path’ (WJ:387; compare also PATA in QL:72), thus *’he who walks a lot’; or rhimp ’rushing, flying’ (RIP-) + #pedir, thus *’rush-walker’ – the latter explanation is closer to ’Trotter’.
Padathir is clearly formed from pata as well, but there are several possibilities for the ending. We know N. †dîr surviving chiefly in proper names (DER-) – here it could be lenited to -ðir and then dissimilated to -þir. Another possibility is the attachment of the ending -ir to the noun #padath ’walking’, compare e.g. tirith ’watch, guard’ (TIR-), although many examples seem to indicate that -th is preferred after r or l in the stem (e.g. mereth ’feast, festival’ (MBER-), meleth ’love’ (MEL-), dalath ’flat surface, plane, plain’ (DAL-), palath ’surface’ (PAL-) and so on).
Another possibility may be a connection with TIR- ’watch, guard’, perhaps via *patat-tir or *padad-tir, but then meaning *’Scout, Ranger’ rather then ’Trotter’.
Du-finnion most probably means *’dark-haired’ < N. dû ’nightfall, late evening’ or ’night, dead of night’ (DOƷ-, DÔ-) + find, finn ’a single hair’ (SPIN-, PE17:17) + name-formative ending -(i)on. Compare durion ’the Dark Elf’. Alternatively we might be dealing with an adjective finnion *’haired, having hair’, see 4.4.
Finally, Ethelion must be connected to Q. ettele ’outer lands’, ?ettelen or ?ettelea ’foreign’ (VT45:13, reading uncertain). Medial -tt- would produce -th- in Noldorin/Sindarin, hence Ethelion *’foreigner’, which is the meaning of ’Peregrin’.