input: Sinatra was known for his sense of style. He always dressed immaculately, both in his professional and private life. He felt that as he was the best, he had to give his best to the audience, and would wear expensive custom-tailored tuxedos on stage as a sign of respect and to look important. He spent lavishly on stylish pin-striped suits and other clothing, and later said that clothing made him feel wealthy and important, bolstering his ego. He was also obsessed with cleanliness--while with the Tommy Dorsey band he developed the nickname "Lady Macbeth", because of frequent showering and switching his outfits. His deep blue eyes earned him the popular nickname "Ol' Blue Eyes".  For Santopietro, Sinatra was the personification of America in the 1950s: "cocky, eye on the main chance, optimistic, and full of the sense of possibility". Barbara Sinatra wrote that "A big part of Frank's thrill was the sense of danger that he exuded, an underlying, ever-present tension only those closest to him knew could be defused with humor". Cary Grant, a friend of Sinatra's, stated that Sinatra was the "most honest person he'd ever met", who spoke "a simple truth, without artifice which scared people", and was often moved to tears by his performances. Jo-Caroll Dennison commented that he possessed "great inner strength", and that his energy and drive was "enormous". A workaholic, he reportedly only slept for four hours a night on average. Throughout his life, Sinatra had mood swings and bouts of mild to severe depression, admitting to an interviewer in the 1950s that "I have an over-acute capacity for sadness as well as elation". Barbara Sinatra stated that he would "snap at anyone for the slightest misdemeanor", while Van Heusen said that when Sinatra got drunk it was "best to disappear".  Sinatra's mood swings often developed into violence, directed at people he felt had crossed him, particularly journalists who gave him scathing reviews, publicists, and photographers. According to Rojek he was "capable of deeply offensive behavior that smacked of a persecution complex". He received negative press for fights with Lee Mortimer in 1947, photographer Eddie Schisser in Houston in 1950, Judy Garland's publicist Jim Byron on the Sunset Strip in 1954, and for a confrontation with Washington Post journalist Maxine Cheshire in 1973, in which he implied that she was a cheap prostitute. In contrast, Sinatra was known for his generosity, particularly after his comeback. Kelley notes that when Lee J. Cobb nearly died from a heart attack in June 1955, Sinatra flooded him with "books, flowers, delicacies", paid his hospital bills, and visited him daily, telling him that his "finest acting" was yet to come. In another instance, after an argument with manager Bobby Burns, rather than apologize, Sinatra bought him a brand new Cadillac.

Answer this question "why did he have mood swings?"
output: directed at people he felt had crossed him, particularly journalists who gave him scathing reviews, publicists, and photographers.

Question: Arabs (; Arabic: `arab ISO 233 'arab, Arabic pronunciation ['?arab] ( listen)) are a population inhabiting the Arab world. They primarily live in the Arab states in Western Asia, North Africa, the Horn of Africa and western Indian Ocean islands.

The earliest documented use of the word "Arab" to refer to a people appears in the Kurkh Monoliths, an Akkadian language record of the ninth century BCE Assyrian conquest of Aram, which referred to Bedouins of the Arabian Peninsula under King Gindibu, who fought as part of a coalition opposed to Assyria. Listed among the booty captured by the army of king Shalmaneser III of Assyria in the Battle of Qarqar are 1000 camels of "Gi-in-di-bu'u the ar-ba-a-a" or "[the man] Gindibu belonging to the Arab (ar-ba-a-a being an adjectival nisba of the noun 'arab). The related word `a'rab is still used to refer to Bedouins today, in contrast to 'arab which refers to Arabs in general.  The oldest surviving indication of an Arab national identity is an inscription made in an archaic form of Arabic in 328 using the Nabataean alphabet, which refers to Imru' al-Qays ibn 'Amr as "King of all the Arabs". Herodotus refers to the Arabs in the Sinai, southern Palestine, and the frankincense region (Southern Arabia). Other ancient Greek historians like Agatharchides, Diodorus Siculus and Strabo mention Arabs living in Mesopotamia (along the Euphrates), in Egypt (the Sinai and the Red Sea), southern Jordan (the Nabataeans), the Syrian steppe and in eastern Arabia (the people of Gerrha). Inscriptions dating to the 6th century BCE in Yemen include the term "Arab".  The most popular Arab account holds that the word "Arab" came from an eponymous father called Ya'rub who was supposedly the first to speak Arabic. Abu Muhammad al-Hasan al-Hamdani had another view; he states that Arabs were called Gharab ("West") by Mesopotamians because Bedouins originally resided to the west of Mesopotamia; the term was then corrupted into "Arab".  Yet another view is held by al-Masudi that the word "Arabs" was initially applied to the Ishmaelites of the "Arabah" valley. In Biblical etymology, "Arab" (in Hebrew Arvi ) comes both from the desert origin of the Bedouins it originally described (Arava means wilderness).  The root '-r-b has several additional meanings in Semitic languages--including "west/sunset," "desert," "mingle," "mixed," "merchant," and "raven"--and are "comprehensible" with all of these having varying degrees of relevance to the emergence of the name. It is also possible that some forms were metathetical from '-B-R "moving around" (Arabic '-B-R "traverse"), and hence, it is alleged, "nomadic."

Using a quote from the above article, answer the following question: What was unique about the etymology of Arabs ?
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Answer:
The related word `a'rab is still used to refer to Bedouins today,