Darwish and Darvish (and in French more prominently Darwich and Darwiche) are alternate transliterations of the Persian word "dervish", used in Arabic: درويش, referring to a Sufi aspirant. There is no v sound in most Modern Arabic dialects and so the originally Persian word is usually pronounced with a w sound in Arabic. The word appears as a surname in the Levant or for people descended from Levantine communities, particularly in Lebanon, Syria, Israel and the Palestinian territories. An etymology for the name is given in the Oxford Dictionary of American Family Names:
Status name for a Sufi holy man, from Persian and Turkish derviş ‘dervish’, a member of a Sufi Muslim religious order, from Pahlavi driyosh meaning ‘beggar’, ‘one who goes from door to door’.