* By letter count: You could find very long words with only one vowel, but they'd be rather boring and likely obscure.
* By syllable count: There are likely words with one vowel that have many syllables, but again, these might not be common words.
Example:
* "Strengths" is a relatively common word with one vowel (the 'e') and seven letters.
It's more fun to consider the concept of a word with only one vowel. It makes you think about how important vowels are in creating sounds and meaning in language.