And just in case you wanted to know the etymology of the word fart is quite interesting:
It cannot but come as a surprise that against the background of countless important words whose origin has never been discovered some totally insignificant verbs and nouns have been traced successfully and convincingly to the very beginning of Indo-European. Fart (“not in delicate use”) looks like a product of our time, but it has existed since time immemorial. Even the nuances have not been lost: one thing is to break wind loudly (farting); quite a different thing is to do it quietly (the now obscure “fisting”). (This fist has nothing to do with fist “clenched fingers” and consequently isn’t related to fisting, a sexual activity requiring, as we are warned, great caution and a lot of tender experience. This reminds me of the instruction Sergei Prokofiev gave to his First Piano Concerto: “Col pugno,” that is ‘with a fist’.)
Both words for the emission of wind (fart and fist) were current in the Old Germanic languages. Frata and físa (the accent over the vowel designates its length, not stress) turned up even in Old Icelandic mythological poems. According to a popular tale, the great god Thor was duped by a giant and spent a night in a mitten, which he took for a house. He was so frightened, as his adversary put it, that he dared neither sneeze nor “fist.” In another poem, the goddess Freyja, notorious for her amatory escapades, was found in bed with her brother and farted (apparently shocked by the discovery).
The words were as vulgar then as they are today. Yet even grammar proves their antiquity. Some verbs (they are called strong) form their principal parts by changing the root vowel, for instance, write/wrote/written, sing/sang/sung. Others (they are called weak) add a dental suffix (d or t) in the preterit and the past participle, for example, beg/begged/begged,look/looked/looked, wait/waited/waited. Strong verbs belong to the most ancient part of the Germanic vocabulary. Fart was one of them; however, it occurred in several forms. Modern German has retained farzen (now a weak verb, though furzen is the most common form) and Furz (a noun). In the older period, German also had furzen and ferzan. Engl. fart goes back to ferten, an exact congener of ferzan. Although it was recorded only in the verbal noun ferting, its existence can be taken for granted. I assume that the group er in it changed to ar in the same way in which person yielded its doublet parson and clerk became Clark(in British English, clerk and Clark are homophones).