Over time I’ve got a lot of strong feedback for my choice in using Derviş / Dervişe for Bhikkhu / Bhikkhunī in my translations: People either love it intensely, or really dislike it. 
Interestingly, the Islamic Mysticism has a strand of open-minded acceptance and tolerance, and many people actually connected with the environment loved the appropriation, while I generally felt more of a push-back from people who were either completely secular or just with a distaste of anything Islamic-sounding.
So I wanted to write my rationale for why I believe Derviş / Dervişe are fine choices for Bhikkhu / Bhikkhunī, perhaps with a strong contention from Zahid / Zahide which I’ve reserved for samaṇa / samaṇī.
I might yet be persuaded, of course. Still.
To anyone who doesn’t speak Turkish, Persian or Arabic, perhaps this piece might also give a clue on the difficulties of porting strong cultural terms to another culture’s vocabulary, and perhaps be an interesting exploration of shared Indo-Aryan Mendicant Culture.
Baggage of Words - Studying Keşiş
In Turkish, there’s already a word for monk, which is keşiş. If we look at the Nişanyan Etymology Dictionary, we can see that it specifies a type of Christian Priests, without even talking about anything monastic. In plain Aramaic, it simply means elder.
According to Turkish Literary Institute, it simply means “Priest”.
In Turkish Wikipedia, it’s primarily explained as Christian Monks, though there’s a group of Thai Buddhist Monks. And most interestingly, it also talks about Islamic Keşiş in the sense of Renunciates, and talks about the very Sufi Mendicant culture I’m alluding to with Derviş.
Turkish Religious Institute explains that there are both Christian and Buddhist keşiş; but the same article also says that male / female keşiş are called upãsakas / upãsikas. 
So, there’s an established meaning in Keşiş, which has Aramaic roots in Elder, over time signifying a certain rank of Priesthood, taking the monastic meaning, and also being applied to Buddhist Monastics in Turkey.
It would be much easier and less contentious, just to stick with it. But I still don’t think that just because we’ve done so so far, doesn’t mean we can’t try and find a better word, a stronger connonation, that signifies the difference from Christian Monasticism to Islamic / Persian Mendicant culture, which has a lot stronger organic ties to the Buddhist Mendicantism.
Pre-Islamic Persian Poverty
Unlike with Christianity in general, Pre-Abrahamic Indian and Persian societies have a shared geography and culture.
The specific word Derviş has roots in Pre-Islamic Zoroastrian culture, particularly that of Dēnkard tradition. We can trace the word to the Zoroastrian ethical vocabulary of sanctified indifference to wealth, crystallised around Middle Persian driyōš (“poor”) and driyōšīh (“pious indigence”).
From Encyclopaedia Iranica:
From all these pronouncements it is clear that the driyōš were a group within the learned clergy, a group whose members sought spiritual merit and salvation in self-imposed indigence, contentment, abstemiousness, diligence, and amicability toward high and low, a description that would fit as well the early Sufi dervishes of Islam, were it not for the absence of the components of asceticism and the monastic and hermetic life, which were characteristic of Islamic dervish orders.
Toil vs Begging
I think one of the sharpest distinctions of Christian Monasticism and that of Islamic & Buddhistic Renunciation is the very important distinction of: How do we eat?
Unlike Christian Monastics (although there are Christian Mendicants orders as well, but the word Monk is not limited to it), Sufi Derviş were for the most part, beggars, with an asterix. Again, by the courtesy of Encyclopaedia Iranica:
Proposed derivations of the term darvīš in folk etymology (e.g., < dar-pīš “in front of the door”) and the notion that it is cognate with daryūza (mendicancy) were no doubt inspired by the practice among many dervishes of begging from door to door (Borhān-e qāṭeʿ , ed. Moʿīn, II, p. 846). There is, however, no essential connection between dervishhood and mendicancy; in fact, it is sometimes held that abstention from begging is the mark of a true dervish.
Begging was a common form of livelihood, but highest derviş even abstained from that.
Continuing in the entry, I think we can find very interesting ideas:
From the 11th century onward the word darvīš was used independently of faqīr. Abu’l-Ḥasan Ḵaraqānī (d. 425/1034) characterized dervishhood as “an ocean fed from three sources: abstention (parhīz), generosity (saḵāwat), and freedom from need (bī-nīāz būdan).” Correcting the definition of a dervish simply as one who has no worldly goods, he observed that, instead, the dervish is “he whose heart is empty of cares; who speaks without awareness of speech; who hears without awareness of hearing; who eats without awareness of tasting; for whom motion and stillness are as one; and for whom grief and joy do not exist” (p. 110). For Ḵᵛāja ʿAbd-Allāh Anṣārī (d. 481/1089) the dervish was one “who does not possess the slightest particle of being.”
On a certain level this description applies to all creatures, but it is only the one who is conscious of its truth who counts as a dervish. Furthermore, “the dervish is one who abandons both this world and the hereafter and does not even have any religion” (in the sense that the dervish has no selfhood, whereas religion presupposes the selfhood of its practitioner). “The dervish must reside nowhere and recognize nothing. . . . He annihilates his own existence in the existence of God; neither mankind nor self remains for him, neither the seeker nor the sought. Such is the attribute of the dervish” (1368 Š./1989, p. 137).
I don’t think we need to look too far to see how this vocabulary is, for the most part, greatly comportable to the ideal bhikkhu / bhikkhunī:
- Derviş doesn’t recognise anything
“Where they stand, the streams of conceiving do not flow. And where the streams of conceiving do not flow, they are called a sage at peace.” MN140 - Derviş abandons this world and the hereafter
“Such a mendicant sheds the near shore and the far, as a serpent its old worn-out skin.” SNP 1.1 - Derviş doesn’t have any religion
“In the same way, I have taught a simile of the teaching as a raft: for crossing over, not for holding on. By understanding the simile of the raft, you will even give up the teachings, let alone what is not the teachings.” MN22 - Derviş has no selfhood
“Tathāgata is not apprehended as real and actual even in the present life.” SN 22.85.
“All Dhamma are not-self.” - Derviş abandons everything, having no joy or grief left
“Good people let go of everything; the peaceful do not prattle about sensuality. Whether they are touched by pleasure or pain, neither elation nor depression can be seen in the wise.” Dhp 83
Fanā & Nibbāna
Crucially, one of the most important topics of Sufi Mysticism, which scholars largely agree that is influenced by Indian thought is the Fanā concept.
Abu Yazid al-Bistami (804–874) introduced the concepts of fanā and khudʿa into Sufism as a result of the influence of his teacher Abu Ali al-Sindi on him. Fanā means the ending of existence, that is, the complete effacement of the individual ego in order to become one with God; khudʿa, on the other hand, means deception or trickery as an explanation of the material world — ringing the Mahāyāna doctrine of māyā. Both concepts are alien to the Arabic Classical Islam.
In Hindu and Muslim Mysticism, R. C. Zaehner argues that al-Sindi, who is known to have converted from another religion, most likely derived the former concept from the Chandogya Upanishad, and that this in turn came from the Svetashvatara Upanishad as interpreted by Shankara (788–820), the founder of Advaita Vedanta.
The topic of Fanā and Nibbāna has been a source of extensive study in the academia. There are a lot of Orientalist Western scholars that find a direct link, as well as Islamic Scholars.
Of course, the soteriology and the language is not the same — and I’m not trying to link that Sufism is the same thing as Buddhism.
Specifically, whether it was the Buddhist or Brahmanical influence over Sufism on its ideal is also contested. It sounds a lot more like Atman dissolving into Brahman, in the Godly-context of Islamic thought.
Still, I want to draw attention to the influence of Indian and particularly Buddhist thought on the development of Sufism, which has been an extensive source of academic investigations.
Are Bhikkhus Derviş?
No.
Coming back to the matter of translation, Sufism is not the same thing as Buddhism, and historical Derviş are not the same thing as Bhikkhus. But we need to use something to translate! 
There was a time that Keşiş only meant Christian Monastic, and after a while, people have extended its usage to other religions. Perhaps the same thing can happen with the word Derviş. Perhaps it’s a pipe dream of mine.
I still think it’s worth the trouble, because I believe the ideals that are brought to mind with derviş are much more strong and resonant than just Christian Monk.
But I hope, at least, this was still an interesting read on a common thread of the Indo-Aryan Mendicant cultures.
