[Ardamir the Blessed]

Beorn is the most obvious example of Tolkien's wordplay that I can think of. It means "man, noble, hero, warrior ..." in Old English, but originally meant "bear" according to Christopher Tolkien. Modern Swedish and Norwegian björn means "bear".



I found this myself in 'Description of the Island of Númenor' which I thought was a bit suspicious:

Vëantur, venturer?

In a way Vëantur was the first 'venturer' of Númenor:

When six hundred years had passed from the beginning of the Second Age Vëantur, Captain of King's Ships under Tar-Elendil, first achieved the voyage to Middle-earth. He brought his ship Entulessë (which signifies "Return") into Mithlond on the spring winds blowing from the west; and he returned in the autumn of the following year. Thereafter seafaring became the chief enterprise for daring and hardihood among the men of Númenor; and Aldarion son of Meneldur, whose wife was Vëantur's daughter, formed the Guild of Venturers, in which were joined all the tried mariners of Númenor

Vëantur probably means something entirely different translated, though.



PM, 'The Problem of ros':

It is also unfortunate that the first [the -ros in 'Elros'] appears too reminiscent of Latin rōs ['dew'] or Greek drosos, and the latter [the -ros in 'Maedhros' and 'Amros'] too close to well-known modern European 'red' words: as Latin russus, Italian rosso, English russet, rust, etc. However, the Elvish languages are inevitably full of such reminiscences, so that this is the lesser difficulty.

That sounds as if almost all of such reminiscences exist by accident; that Tolkien could not help that many words ended up similar to modern words or he did not care, or perhaps he used modern words as inspiration for some of his invented words and therefore they are similar.