bad guy

English Wikipedia has an article on:

villain

Wikipedia

bad guy (plural bad guys)

(informal) a villain, particularly an antagonist in a story.
- 2023 March 14, Caryn James, “John Wick: Chapter 4: 'Soars above most action films'”, in BBC‎:
  Perversely, we love John Wick himself. That lethal, bereaved assassin is a good bad guy for our times, the natural extension of Tony Soprano, Walter White and all the other heroic antiheroes the culture has embraced.

a villain

Chinese:
Mandarin: 壞人 / 坏人 (zh) (huàirén), 壞蛋 / 坏蛋 (zh) (huàidàn), 惡人 / 恶人 (zh) (èrén)
Danish: skurk c
Finnish: pahis (fi), vastustaja (fi)
French: méchant (fr) m, mauvais (fr) m, salaud (fr) m (informal)
German: Bösewicht (de) m, Böser (de) m (informal), Missetäter (de) m (elevated), Schurke (de) m
Indonesian: orang jahat (id)
Italian: cattivista m
Japanese: 悪者 (ja) (わるもの, warumono), 悪人 (ja) (あくにん, akunin, わろびと, warubito)
Korean: 악인 (ko) (agin)
Russian: плохо́й па́рень m (ploxój párenʹ) (calque from English), злоде́й (ru) m (zlodéj), плохо́й (ru) m (ploxój)
Swedish: bov (sv) c, skurk (sv) c, ful typ c