Dervish is really a mysterious word, in the Middle Persian translations of the Bible, this word has been used for "Apostle" and in the Sogdian translations of the Buddhist texts, this is the translation of "Bhikkhu" but what does this word mean?
As you read here:
http://en.wikipedia.org/wiki/Dervish "there have been attempts to make the parts of the word interpretable in terms of contemporary words and with reference to Sufic mystical concepts.
Dar in
Persian means "a door", so
Dervish is said to literally mean "one who opens the doors".
"
Does "vish" mean "one who opens" in Persian?!! I think that is certainly a fake etymology.
Druid
c.1500, from O.Fr. druide, from L. Druidae (pl.), from Gaulish Druides, from O.Celt. *derwijes, representing O.Celt. derwos "true" and *dru- "tree" (especially oak) + *wid- "to know" (cf. vision).