What is a Darvish? (Dervish/Darwish/Sufi)

The Persian word darvīsh (درویش) is of ancient origin and descends from a Proto-Iranian word that appears in Avestan as drigu-, "needy, mendicant", via Middle Persian driyosh.  The Iranian word is probably a cognate with the Vedic Sanskrit word adhrigu-, an epithet of uncertain meaning applied to several deities. The Vedic word is probably to be analysed as a-dhrigu-, that is "not dhrigu-," perhaps "not poor", i.e. "rich." The existence of this Vedic cognate suggests that the institution of the holy mendicant was as prominent among the ancient Indo-Iranian people as it has been historically in later Iran in the form of dervish brotherhoods and also in India in the form of the various schools of sannyasis.  However, because the etymology of the word is not apparent from the point of view of the modern Persian language, 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"; "dervish" has been interpreted as "one who goes from door to door".  The Persian word also gives terms for "ascetic" in some languages, as in the Urdu phrase darveshaneh tabi'at, "an unflappable or ascetic temperament".

Many Dervishes are mendicant ascetics who have taken a vow of poverty, unlike mullahs. The main reason they beg is to learn humility, but Dervishes are prohibited to beg for their own good. They have to give the collected money to other poor people. Others work in common professions; Egyptian Qadiriyya – known in Turkey as Kadiri – are fishermen, for example.

Some classical writers indicate that the poverty of the Dervish is not merely economic. Saadi, for instance, who himself travelled widely as a dervish, and wrote extensively about them, says in his Gulistan:

Of what avail is frock, or rosary, Or clouted garment? Keep thyself but free
From evil deeds, it will not need for thee
To wear the cap of felt: a darwesh be
In heart, and wear the cap of Tartary.

Rumi writes in Book 1 of his Masnavi:

Water that's poured inside will sink the boat
While water underneath keeps it afloat.
Driving wealth from his heart to keep it pure
King Solomon preferred the title 'Poor':
That sealed jar in the stormy sea out there
Floats on the waves because it's full of air,
When you've the air of dervishood inside
You'll float above the world and there abide...

This is the closest thing to a "Monk" in Islam and the Sufis or Dervishes/Darvishes who take up arms in defense are similar to Christian "Templars" or "Warrior Monks".   The Ottoman Janissaries or Safavid Qizilbash are good examples of Warrior Monks of Islam.