Verbs don't describe, they are doing words... adjectives are used to describe things. It depends what sort of thing you are looking for but you could use words like evil, nasty, cruel, horrid, etc.
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adjective form of villain is "Villainous"
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Rather than quote verbatim, I'll err on the side of caution and simply direct you to my preferred on-line vocabulary information source Merriam-Webster.
For vocabulary questions, Merriam-Webster is an excellent resource I use frequently; the search box presents possible word selections as one types, which is often enough to direct the inquirer (or even provide the answer, if spelling was the heart of the question).
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A villain can be described as criminal, evil, destructive, antisocial, perhaps misguided, dangerous, bad.
Yes, arch can be an adjective, meaning either principal or mischievous. Examples : an arch foe, an arch glance (It may be a prefix, or hyphenated form, in words such as archbishop, archrival or arch-villain)
The adjective form is patient.
The adjective form is familiar.
The adjective form is comedic.
The adjective form is kingly.