Vowels in English are A. E. I. O. and U. They are found in only one word- nefarious. So, you aver, isn’t Y a vowel too? OK, let’s add that to Nefariously.
ne·far·i·ous
nəˈferēəs/
adjective
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(typically of an action or activity) wicked or criminal.“the nefarious activities of the organized-crime syndicates”
synonyms: wicked, evil, sinful, iniquitous, egregious, heinous, atrocious, vile, foul,abominable, odious, depraved, monstrous, fiendish, diabolical,unspeakable, despicable;