Impossible!
That is just impossible. Actually, every single word in the whole entire English language has a vowel in it. So it is impossible to say a word in the English language with no vowels. Only some abbreviations don't have vowels, but they are not words so they don't count.
Now take the word F-L-Y for example. There is no A in it. There is no E in it. There is no I in it. There is no O in it. And there is no U in it. But there is a Y. And a Y is sometimes considered a vowel because in the word, the Y makes the sound of a long I. In other words the Y may sound like a E, like in the word key.
Rhythms is a seven letter word that contains no vowels.
Pygmy or gypsy
THEREIN
therein
Therein
The longest word in the English language without a vowel is "rhythms." It has seven letters and does not contain any vowels.
Yes, vowels can also be referred to as "vocalic sounds."
Yes, many.Some, such as facetious have five.
No, the word, boosjy, is not a word in the English language. Any word that is in the English language can be found in the dictionary.
No, that word is not a word in the English language or any language that I am aware of.
These are the five standard (classic) vowels in the English language A E I O U , to which may be added the "semi-vowel" Y, and also W in Welsh.
There isn't any natural language composed only of vowels.
There is no word listed in English or in any other language in that question.
English doesn't have 25 vowels.
IOU (A note promising to pay someone some money you owe them.) is considered a word by some dictionaries. Other dictionaries use I.O.U. (So it may or may not be a 'word' for the purposes of the question. I can't think of any other word which meets the requirements. A more usual form of the question is "What word in the English language contains all the vowels in alpahbetical order?" There are two answers to THAT question Abstemious - and - Facetious
The longest word without vowels is "rhythms." It has 7 letters and does not contain any vowels.
The most obvious is 'rhythm' although there are probably many more.